TELEPHONE (Gr.
.^ TilXe, far, and qk vrl, voice).
.^ Telephony is the art of reproducing sounds at a distance from their source, and a telephone is the instrument employed in sending or receiving such sounds.
^ This only answers, however, for telephoning musical sounds to short distances.
^ The undefined sources were, in essence, a precaution by me to cover myself where sources occurred from uncommon or a new implementations in SIM, or simlar from external sources, such as mobile telephones.- Mobile Telephone Evidence: 11/01/2006 - 12/01/2006 11 September 2009 9:42 UTC trewmte.blogspot.com [Source type: FILTERED WITH BAYES]
.^ The term " telephony " was first used by Philipp Reis of Friedrichsdorf , in a lecture delivered before the Physical Society of Frankfort in 1861.1 But, although this lecture and Reis's subsequent work received considerable notice, little progress was made until the subject was taken up between 1874 and 1876 by Alexander Graham Bell , a native of Edinburgh , then resident in Boston , Mass., U.S.A. Bell , like Reis, employed electricity for the reproduction of sounds; but he attacked the problem in a totally different manner.
^ This inventive schoolteacher was Alexander Graham Bell.- American Experience . Technology . The Telephone . The Film & More | Program Transcript | PBS 11 January 2010 10:40 UTC www.pbs.org [Source type: FILTERED WITH BAYES]
^ The Mobile Mania In todays date, where we more than thank Alexander Graham Bell for inventing the telelphone, its also interesting to note that mot mobile phone users are known to match their personalities with the mobile instrument that they use.- Cell Phones 31 January 2010 13:24 UTC www.buzzle.com [Source type: FILTERED WITH BAYES]
.^ This will be better understood if we consider shortly on what the chief characteristics of sound depend.
.^ The sensation of sound is produced by rapid fluctuation in the pressure of the atmosphere on the tympanum of the Charac- ear .
^ If the fluctuations are irregular and non-periodic, teristics the sound is called a noise ; if they are cyclic and follow a regular and sufficiently rapid periodic law, the sound is musical.
^ When the connecting string is held taut and sounds, such as those of ordinary speech, are produced in front of one of the membranes, pulses corresponding to the fluctuations of the atmospheric pressure are transmitted along the string and communicated to the other membrane, which in its turn communicates them to the air , thus reproducing the sound.
.^ If the fluctuations are irregular and non-periodic, teristics the sound is called a noise ; if they are cyclic and follow a regular and sufficiently rapid periodic law, the sound is musical.
^ The sensation of sound is produced by rapid fluctuation in the pressure of the atmosphere on the tympanum of the Charac- ear .
^ Here in Maine they just passed a law called distracted driving.- Cell Phone Laws | WRKO 31 January 2010 13:24 UTC audio.wrko.com [Source type: Original source]
.^ In connexion with the present subject it is important to notice the three characteristics of a musical sound, namely, pitch , loudness and quality.
^ The pitch of a musical sound depends on the number of cycles passed through by the fluctuations of the pressure per unit of time; the loudness depends on the amount or the amplitude of the fluctuation in each cycle ; the quality depends on the form or the nature of the fluctuation in each cycle.
^ If the fluctuations are irregular and non-periodic, teristics the sound is called a noise ; if they are cyclic and follow a regular and sufficiently rapid periodic law, the sound is musical.
.^ The necessary condition for a successful system of telephony is the ability to reproduce these characteristics.
^ In both these examples all the three characteristics - pitch, relative intensity, and quality - of sound are reproduced.
.^ Ober Telephonie durch den galvanischen Strom," in Jahresber.
d. physikalischen
.^ Vereins zu Frankfurt am Main, 1860-61, p.
57.
.^ In 1831 Wheatstone by his " magic lyre " experiment showed that, when the sounding -boards of two musical instruments are connected together by a rod of pine wood, a tune played on one will be faithfully reproduced by the other.
^ This apparatus has two coils, one of which, connected across the line, is provided for the purpose of projecting the shutter, while the other is intended for its restoration and is joined in a local circuit arranged to be closed when a plug is inserted in any one of the associated jacks.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
.^ This only answers, however, for telephoning musical sounds to short distances.
^ In consequence of their high capacity, the attenuation constant of submarine cables is high, and only a small number of cables, of comparatively short length, are in use for telephonic purposes.
^ Minnesota, however, only reports the presence of a cellular telephone; not its use.- An Investigation of the Safety Implications of Wireless Communications in Vehicles DOT TOC 16 September 2009 22:41 UTC www.nhtsa.dot.gov [Source type: Reference]
.^ A system of wires, similar to that which connects the district exchanges in an area, links together the various local areas in the territory, and sometimes the territory of one administration with that of another.
^ The mobile communication exchanges are interconnected by transit switches, and each is connectable to a public switched telephone network or similar fixed network or to another mobile communication network via, e.g., a gateway office.- US Patent 6477364 - Automatic redialing method for a mobile communication network and a mobile communication system 20 September 2009 18:50 UTC www.wikipatents.com [Source type: Reference]
^ Another and somewhat similar example is furnished by what has been variously designated as the " string," toy ," " lovers," and " mechanical " telephone.
.^ RJ11 , 12 or 45 Connect two Cables together to extend the cable.- Telephone Cables, Modem Cables, Couplers, splitters, Wireless Telephone Jacks 11 January 2010 10:40 UTC www.action-electronics.com [Source type: General]
.^ A good example may be made with two cylindrical tin cups; the bottoms form the membranes and the cups the mouthpieces.
^ Again, the form of the opening or mouthpiece in front of the membrane exercised considerable 1 See A. G. Bell, " Telephone Researches," in Journ.
^ Two disks of thin metal , or two stretched membranes, each furnished with a mouthpiece , are connected together by a thin string or wire attached at each end to the centres of the membranes.
.^ The sensation of sound is produced by rapid fluctuation in the pressure of the atmosphere on the tympanum of the Charac- ear .
^ When the connecting string is held taut and sounds, such as those of ordinary speech, are produced in front of one of the membranes, pulses corresponding to the fluctuations of the atmospheric pressure are transmitted along the string and communicated to the other membrane, which in its turn communicates them to the air , thus reproducing the sound.
^ In 1831 Wheatstone by his " magic lyre " experiment showed that, when the sounding -boards of two musical instruments are connected together by a rod of pine wood, a tune played on one will be faithfully reproduced by the other.
.^ In both these examples all the three characteristics - pitch, relative intensity, and quality - of sound are reproduced.
^ In connexion with the present subject it is important to notice the three characteristics of a musical sound, namely, pitch , loudness and quality.
^ As we have increased our exposure to both chemicals and EMFs in the last three decades we have seen certain brain cancers increase in all age groups by 1% a year.- Cell Phones 31 January 2010 13:24 UTC tuberose.com [Source type: Academic]
.^ In July 1837 Dr C. G. Page of Salem, Mass., drew attention to the sound given out by an electromagnet at the instant when the electric circuit is closed or broken, and in October of the same year he discussed, in a short article a entitled " Galvanic Music ," the musical note pro- covery.
^ His first idea seems to have been to employ the vibrations of the current in an electric circuit, produced by moving the armature of an electromagnet included in the circuit nearer to or farther from the poles of the magnet.
^ The writer recommended the use of a flexible plate at the source of sound, which would vibrate in response to the varying pressure of the bons' air, and thus open and close an electric circuit, and of a similar plate at the receiving station, which would be acted on electromagnetically and thus give out as many pulsations as there are breaks in the current.
.^ Experiments bearing on this subject were subsequently made by a great number of investigators.4 Page's discovery is of considerable importance in connexion with the theory of action of various forms of telephone, and was a very important feature in the early attempts by Reis to transit music and speech.
^ The records of the telephone industry in Great Britain during the thirty years from 1877 to 1907 form an instructive chapter in the industrial history of the country.
^ The Cellular Telecommunications Industry Association (CTIA), various manufacturers as well as service providers have specifically focused on safe driving as an important consideration relating to cellular telephone use.- An Investigation of the Safety Implications of Wireless Communications in Vehicles DOT TOC 16 September 2009 22:41 UTC www.nhtsa.dot.gov [Source type: Reference]
.^ This is a very interesting article but I cannot seem to get the graphics to appear despite trying from a number of different machines and browsers.- Mobile Phones for Data Collection | MobileActive.org 28 January 2010 1:30 UTC mobileactive.org [Source type: FILTERED WITH BAYES]
^ The company's interest appears to be simple: there are more than a billion mobile phones in the world, and sales show no signs of slowing down.- mobile phone posts - Webware - CNET 28 January 2010 1:30 UTC news.cnet.com [Source type: General]
.^ The writer recommended the use of a flexible plate at the source of sound, which would vibrate in response to the varying pressure of the bons' air, and thus open and close an electric circuit, and of a similar plate at the receiving station, which would be acted on electromagnetically and thus give out as many pulsations as there are breaks in the current.
^ In July 1837 Dr C. G. Page of Salem, Mass., drew attention to the sound given out by an electromagnet at the instant when the electric circuit is closed or broken, and in October of the same year he discussed, in a short article a entitled " Galvanic Music ," the musical note pro- covery.
^ Sir W. Thomson (Lord Kelvin) observed in 1863 3 that when a condenser is charged or discharged, a sharp click is heard, and a similar observation was made by Cromwell F. Varley, who proposed to make use of it in a telegraphic receiving instrument.4 In Dolbear's instrument one plate of a condenser was a flexible diaphragm, connected with the telephone line in such a way that the varying electric potential produced by the action of the transmitting telephone caused an increased or diminished charge in the condenser.
.^ In both these examples all the three characteristics - pitch, relative intensity, and quality - of sound are reproduced.
^ These suggestions were to some extent an anticipation of the work of Reis; but the conditions to be fulfilled before the sounds given out at the receiving station can be similar in pitch, quality and relative intensity to those produced at the transmitting station are not stated, and do not seem to have been appreciated.
^ It sometimes occurs that the channel between the mobile station and the base station cannot be set up due to channel congestion or some other similar cause.- US Patent 6477364 - Automatic redialing method for a mobile communication network and a mobile communication system 20 September 2009 18:50 UTC www.wikipatents.com [Source type: Reference]
.^ In Reis's lecture an apparatus was described which has given rise to much discussion as to priority in the invention of the telephone.
^ The draft agreement between the government and the National Telephone Company to carry out the policy of 1892 was submitted to parliament and led to much discussion.
.^ The instrument was described in over fifty publications 6 in various countries, and was well known to physicists previous to Bell's introduction of the electric telephone as a competitor with the electric telegraph .
^ Various states already have such laws in place, as well as certain cities across the country.
^ Western Electric manufactured telephones for both Bell telephone and Western Union.- Cybertelecom :: Telephone 11 January 2010 10:40 UTC www.cybertelecom.org [Source type: FILTERED WITH BAYES]
Reis caused a membrane to open and
close an electric 2 See his
Scientific Papers, P. 47.
a
.^ See Silliman's Jour., xxxii.
396, and xxxiii.
118.
4 Marrian,
Phil. . 3rd ser., vol.
^ Mag., 3rd ser., vol.
^ Mag., 5th ser., vol.
xxv. p. 382;
Beatson,
Arch. de l'Elect., v.
.^ De la Rive, Treatise on Electricity, i.
306, also
Phil. .
3rd ser., vol.
^ Mag., 3rd ser., vol.
^ Mag., 5th ser., vol.
xxxv. p. 422, and
Comp. Rend., xx. 1287,
xxii. 432; Matteucci,
Arch. de l'Elect., v. 389;
Guillemin,
Comp. Rend., xxii. 264; Wertheim,
Comp.
Rend., xxii. 33 6, 544, xxvi. 505, also
Ann. de Chim. et
de Phys., xxiii. 302, and
Phil. . 3rd ser., vol.
^ Mag., 3rd ser., vol.
^ Mag., 5th ser., vol.
xxviii. p. 544; Jannair,
Comp. Rend., xxiii. 319; Joule,
Phil. . 3rd ser., vol.
^ Mag., 3rd ser., vol.
^ Mag., 5th ser., vol.
xxv. pp. 76, 225; Laborde,
Comp. . 1.692; Poggendorff,
Pogg.^ Rend., 1.692; Poggendorff, Pogg.
Ann.,
lxxxvii. 139, xeviii.
.^ Du Moncel, Exp.
de l'Elect.,
ii. 125, iii. 83; and Delesenne,
Bibl. Univ. (1841),
xvi. 406.
.^ See also Didaskalia: Blatter fib' Geist, Gemiith, u.
.^ Publiciteit, Frankfort, No.
.^ September 1854; Du Moncel, Expose des Applications de l'Electricite (Paris), ii.
25, ed. 1854; iii. 110, ed. 1856, and
Comp. Rend.,
26th November 1877.
.^ The English reader may consult - Jour.
Soc. Tel.
. March 1883;
British Assoc.^ Eng., March 1883; British Assoc.
. 1863;
Civ.^ Rep., 1863; Civ.
Eng. and Arch. Jour., xxvi.
.^ R. M. Ferguson, Electricity (London, 1866), p.
257; S. P. Thompson,
Philipp Reis, the Inventor of the Telephone (London,
1883).
circuit at each vibration, thus transmitting as many electric
pulses through the circuit as there were vibrations in the sound.
.^ These electric pulses were made to act on an electromagnet at the receiving station, which, in accordance with Page's discovery, gave out a sound of a pitch corresponding to the number of times it was magnetized or demagnetized per second.
^ In July 1837 Dr C. G. Page of Salem, Mass., drew attention to the sound given out by an electromagnet at the instant when the electric circuit is closed or broken, and in October of the same year he discussed, in a short article a entitled " Galvanic Music ," the musical note pro- covery.
^ The writer recommended the use of a flexible plate at the source of sound, which would vibrate in response to the varying pressure of the bons' air, and thus open and close an electric circuit, and of a similar plate at the receiving station, which would be acted on electromagnetically and thus give out as many pulsations as there are breaks in the current.
.^ The science required to send the human voice clear across the United States simply did not exist.- American Experience . Technology . The Telephone . The Film & More | Program Transcript | PBS 11 January 2010 10:40 UTC www.pbs.org [Source type: FILTERED WITH BAYES]
.^ The consonants are for the most part reproduced pretty distinctly, but not the vowels as yet in an equal degree."
.^ Considering the time at which he wrote, Reis seems to have understood very well the nature of the vibrations he had to reproduce, but he failed to comprehend how they could be reproduced by electricity.
^ TALK IS NOT CHEAP Narrator: In the summer of 1876, Bell and Watson were convinced the telephone could make money; they just didn't know how.- American Experience . Technology . The Telephone . The Film & More | Program Transcript | PBS 11 January 2010 10:40 UTC www.pbs.org [Source type: FILTERED WITH BAYES]
^ If they simply weighted by age, Keeter wrote, pollsters would have "eliminated most of the bias that could occur from the underrepresentation of younger, more liberal voters."- Pollster.com: Cell Phones and Political Surveys: Part I 31 January 2010 13:24 UTC www.pollster.com [Source type: FILTERED WITH BAYES]
.^ His fundamental idea - the interruption of the current - was a fatal mistake, which was not at the time properly understood.
.^ The suggestion of Bourseul and the experiments of Reis are founded on the idea that a succession of currents, corresponding in number to the successive undulations of the pressure on the membrane of the transmitting instrument, could reproduce at the receiving station sounds of the same character as those produced at the sending station.
^ In 1831 Wheatstone by his " magic lyre " experiment showed that, when the sounding -boards of two musical instruments are connected together by a rod of pine wood, a tune played on one will be faithfully reproduced by the other.
^ These suggestions were to some extent an anticipation of the work of Reis; but the conditions to be fulfilled before the sounds given out at the receiving station can be similar in pitch, quality and relative intensity to those produced at the transmitting station are not stated, and do not seem to have been appreciated.
.^ Neither of them seemed to recognize anything as important except pitch and amplitude, and Reis thought the amplitude was to some extent obtained by the varying length of contact in the transmitting instrument.
^ Multipath interference: Because the transmitted signal may travel over multiple paths of differing loss and length, the received signal in mobile communications varies rapidly in both amplitude and phase as the multiple signals reinforce or cancel one another.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ These suggestions were to some extent an anticipation of the work of Reis; but the conditions to be fulfilled before the sounds given out at the receiving station can be similar in pitch, quality and relative intensity to those produced at the transmitting station are not stated, and do not seem to have been appreciated.
.^ This might possibly be true to a small extent; but, considering the small capacity of the circuits he used and the nature of his receiving instrument, it is hardly probable that duration of contact sensibly influenced the result.
^ Another type of microphone which was used in Europe much more than in the United States was the multiple-contact instrument.
^ In consequence of their high capacity, the attenuation constant of submarine cables is high, and only a small number of cables, of comparatively short length, are in use for telephonic purposes.
.^ STOCK ("Telephone Memories"): WATSON I could recognize the sound of Bell's voice and could almost understand some of his words.- American Experience . Technology . The Telephone . The Film & More | Program Transcript | PBS 11 January 2010 10:40 UTC www.pbs.org [Source type: FILTERED WITH BAYES]
.^ The next worker at the telephone, and the one to whom the present great commercial importance of the instrument is due, Bell's re- was Bell.
^ Bell's First Telephone (1875); one-fifth full size.
^ Chapter 5 presents a comprehensive review of simulator, and on-the-road, instrumented vehicle research conducted on cellular telephone use while driving.- An Investigation of the Safety Implications of Wireless Communications in Vehicles DOT TOC 16 September 2009 22:41 UTC www.nhtsa.dot.gov [Source type: Reference]
.^ His aim was the production, by means of the undulations of pressure on a membrane caused by sound, of an electric current the strength of which should at every instant vary directly as the pressure varied).
^ Hence, when the undulating telephonic currents were made to pass through the apparatus, the constant variation of the friction of the spring caused the deflexions of the diaphragm to vary in unison with the variation of the electric The extreme smallness of the magnets which might be successfully employed was first demonstrated by Professor Peirce of Brown University, Providence , R.I. .
^ When the current passed, the friction was felt to increase, and the effect of sending a rapidly undulating current through the arrangement was to produce a sound.
.^ His first idea seems to have been to employ the vibrations of the current in an electric circuit, produced by moving the armature of an electromagnet included in the circuit nearer to or farther from the poles of the magnet.
^ Hence, when the undulating telephonic currents were made to pass through the apparatus, the constant variation of the friction of the spring caused the deflexions of the diaphragm to vary in unison with the variation of the electric The extreme smallness of the magnets which might be successfully employed was first demonstrated by Professor Peirce of Brown University, Providence , R.I. .
^ The writer recommended the use of a flexible plate at the source of sound, which would vibrate in response to the varying pressure of the bons' air, and thus open and close an electric circuit, and of a similar plate at the receiving station, which would be acted on electromagnetically and thus give out as many pulsations as there are breaks in the current.
.^ He proposed to make the armature partake of the vibrations of the atmosphere either by converting it into a suitable vibrator or by controlling its vibrations by a stretched membrane of parchment armature had the form of a hinged lever one end, which pressed against the centre.
^ M was a membrane stretched by a ring R over the end of a tube T fixed at one side of the frame F. To the opposite side of the frame an electromagnet I was fixed with its axis in line with the tube T, and between the end of the electromagnet and the membrane a hinged armature A was arranged in such a way that its motion could be controlled by the membrane.
^ He proposed to introduce into the circuit a cell containing carbon powder, the pressure on which could be varied by the micro- vibrations of a diaphragm.
Fig. i shows the arrangement.
.^ M was a membrane stretched by a ring R over the end of a tube T fixed at one side of the frame F. To the opposite side of the frame an electromagnet I was fixed with its axis in line with the tube T, and between the end of the electromagnet and the membrane a hinged armature A was arranged in such a way that its motion could be controlled by the membrane.
^ He proposed to make the armature partake of the vibrations of the atmosphere either by converting it into a suitable vibrator or by controlling its vibrations by a stretched membrane of parchment armature had the form of a hinged lever one end, which pressed against the centre.
^ I radio or CD or even eat it a 100% in the control of that person group doing it -- one way interaction.- Cell Phone Laws | WRKO 31 January 2010 13:24 UTC audio.wrko.com [Source type: Original source]
.^ The instrument was joined in circuit with a battery and another similar instrument placed at a distance; and a continuous current was made to flow through the circuit, keeping the electromagnets energized.
^ Landline telegraphs used a key to make or break an electrical circuit, a battery to produce power, a single line joining one telegraph station to another and an electromagnetic receiver or sounder that upon being turned on and off, produced a clicking noise.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ His first idea seems to have been to employ the vibrations of the current in an electric circuit, produced by moving the armature of an electromagnet included in the circuit nearer to or farther from the poles of the magnet.
.^ The experiments with this form were not successful, and, with the view of making the moving parts as light as possible, he substituted for the comparatively heavy lever armature a small piece of clock spring, about the size of a sixpence, glued to the centre of the diaphragm .
^ It is attached to a brass disk E, which is fastened to the centre of the diaphragm F by means of a rivet , and is capable of moving to and fro like a plunger when the diaphragm vibrates.
^ He proposed to make the armature partake of the vibrations of the atmosphere either by converting it into a suitable vibrator or by controlling its vibrations by a stretched membrane of parchment armature had the form of a hinged lever one end, which pressed against the centre.
.^ The magnet was mounted with its end carrying the coil opposite, and very close to, the centre of the piece of clock spring.
^ The experiments with this form were not successful, and, with the view of making the moving parts as light as possible, he substituted for the comparatively heavy lever armature a small piece of clock spring, about the size of a sixpence, glued to the centre of the diaphragm .
.^ This answered sufficiently well to prove the feasibility of the plan, and subsequent experiments were directed to the discovery of the best form and arrangement of the parts.
^ A significant research effort, including well-planned animal experiments, is needed to provide the basis to assess the risk to human health of wireless communications devices.- Cell Phones 31 January 2010 13:24 UTC tuberose.com [Source type: Academic]
^ The business subsequently proved profitable, good dividends were paid, and the securities for the most part commanded a premium in the market.
.^ An increase in the size of the iron disk attached to the membrane augmented both the loudness and the distinctness of the sounds, and this finally led to the adoption of a thin iron disk supported round its edge, acting as both membrane and armature (fig.
^ D of thin sheet iron; in front of this was a cover M, M provided with a suitable cavity for directing the sound-waves against the diaphragm.
^ To the brass bottom of the case is attached 'a thin disk of polished hard carbon C, which is slightly less in diameter than the brass bottom, so that the carbon disk almost entirely covers this brass back, leaving only a slight annular space around its edge.
2).
.^ Again, the form of the opening or mouthpiece in front of the membrane exercised considerable 1 See A. G. Bell, " Telephone Researches," in Journ.
^ The Telephone Company, Limited, was formed to acquire Bell's patent.
^ A good example may be made with two cylindrical tin cups; the bottoms form the membranes and the cups the mouthpieces.
Soc Tel. Eng., 31st October
1877.
influence on the efficiency of the instrument, and it was
ultimately ascertained that a small central opening, with a thin
air space extending across the face of the membrane, was best.
.^ It was also found that comparatively small magnets were sufficient, and that there was no particular virtue in the closed circuit and electromagnet, but that a small permanent magnet having one pole in contact with FIG. 2.
^ There's no real advantage to having either one.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ The telephone was switched out of circuit when not in use and the bell put in its place, a key being used for throwing the battery into circuit to make the signal .
.^ It was also found that comparatively small magnets were sufficient, and that there was no particular virtue in the closed circuit and electromagnet, but that a small permanent magnet having one pole in contact with FIG. 2.
^ M, permanent magnet; E, electromagnet; C, diaphragm; t t,, terminals.
the end of the core of a short electromagnet, the coil of which
was in circuit with the line, but which had no permanent current
flowing through it, answered the purpose quite as well.'
.^ The apparatus thus acted as both a transmitter and a receiver ; indeed it is essentially the magneto-receiver which has come into universal use in practical telephony, though for transmission it was soon superseded by forms of microphonic transmitters.
^ A type of transmitter which has come to be invaluable in connexion with long distance telephony, and which has practically superseded all other forms, is the granular carbon transmitter.
^ The next transmitter of note was that introduced by Francis Blake, which came into wide use in the United States of America a.nd other countries.
.^ One of the latest forms of FIG. 3.
^ It was also found that comparatively small magnets were sufficient, and that there was no particular virtue in the closed circuit and electromagnet, but that a small permanent magnet having one pole in contact with FIG. 2.
^ Double Pole Receiver.
receiver, known as the double pole, is shown in fig. 3. M and M'
are two permanent magnets; P and P' are soft iron pole-pieces upon
which are placed the electromagnet coils C and C'; D is the
diaphragm; I is a soft iron distance piece placed between the
magnets at the end remote from the diaphragm; B is the
brass body of the instrument, over
which is placed a thin ebonite
shell S. E is the ear-piece made of ebonite; F is
a cap of the same material enclosing the receiver terminals, which
are mounted upon the ebonite block G, attached to the distance
piece I.
.^ A telephone transmitter and a receiver on a novel plan were patented in July 1877 by Edison, shortly after the introduction of Bell's instruments.
^ On the 4th of April 1877 Emile Berliner filed a caveat in the United States patent office, in which he stated that, on the principle of the variation with pressure of the resistance at the contact of two conductors, he had made an instrument which could be used as a telephone transmitter, and that, in consequence of the mutual forces between the two parts of the current on the two sides of the point of contact, the instrument was capable of acting as a receiver.
^ Edison's telephone patent was granted for the United Kingdom.
.^ The receiver was based on the change of friction produced by the passage of an electric current through the point of contact of certain substances in relative motion.
^ When the current passed, the friction was felt to increase, and the effect of sending a rapidly undulating current through the arrangement was to produce a sound.
^ His first idea seems to have been to employ the vibrations of the current in an electric circuit, produced by moving the armature of an electromagnet included in the circuit nearer to or farther from the poles of the magnet.
.^ In one form a drum , mounted on an axis and covered by a band of paper soaked in a solution of caustic potash, was turned under a spring the end of which was in contact through a platinum point with the paper.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ The spring was attached to the centre of a diaphragm in such a way that, when the drum was turned, the friction between the point of the spring and the paper deflected !
.^ The spring was attached to the centre of a diaphragm in such a way that, when the drum was turned, the friction between the point of the spring and the paper deflected !
^ In one form a drum , mounted on an axis and covered by a band of paper soaked in a solution of caustic potash, was turned under a spring the end of which was in contact through a platinum point with the paper.
^ And but that's quite such a great temptation and that's why I have come to the point literally -- I turn this thing off and I need to put it in my purse.- Cell Phone Laws | WRKO 31 January 2010 13:24 UTC audio.wrko.com [Source type: Original source]
the diaphragm.
.^ The current from the line was made to pass through the spring and paper to the cylinder .
^ Hence, when the undulating telephonic currents were made to pass through the apparatus, the constant variation of the friction of the spring caused the deflexions of the diaphragm to vary in unison with the variation of the electric The extreme smallness of the magnets which might be successfully employed was first demonstrated by Professor Peirce of Brown University, Providence , R.I. .
^ When the current passed, the friction was felt to increase, and the effect of sending a rapidly undulating current through the arrangement was to produce a sound.
.^ The current from the line was made to pass through the spring and paper to the cylinder .
^ Now it had been previously shown by Edison that, when a current was made to pass through an arrangement like that just described, the friction between the paper and the spring was greatly diminished.
^ Hence, when the undulating telephonic currents were made to pass through the apparatus, the constant variation of the friction of the spring caused the deflexions of the diaphragm to vary in unison with the variation of the electric The extreme smallness of the magnets which might be successfully employed was first demonstrated by Professor Peirce of Brown University, Providence , R.I. .
Hence,
when the undulating telephonic currents were made to pass through
the apparatus, the constant variation of the friction of the spring
caused the deflexions of the diaphragm to vary in unison with the
variation of the electric The extreme smallness of the magnets
which might be successfully employed was first demonstrated by
Professor Peirce of Brown University,
Providence, R.I.
,?.?;??...
- i. i. ??_,..... .^ In the early trials the of iron carrying a stud at of a stretched membrane FIG. 1.
^ Bell's First Telephone (1875); one-fifth full size.
^ The difficulty was first satisfactorily overcome in the long-distance transmitter, invented by A. C. White in the laboratory of the American Bell Telephone Company, and commonly known as the " solid back transmitter " (fig.
.^ Edison's Microphone Transmitter.
currents, and sounds were given out corresponding in pitch, and
also to some extent in quality, with the sounds produced at the
transmitting station.
.^ A cylinder of chalk was used in some of Edison's later experiments with this receiver.
The transmitter (fig.
.^ G; on the top of G was a layer of carbon powder C, on the top of that a platinum disk D, and above that again, forming the cover of the cell, a disk of ivory B, held in position by a ring E. Resting on the centre of the ivory disk was a small piece of rubber tubing, and this was lightly pressed by the diaphragm A, which was held in place by the mouthpiece M. The varying pressure on A, when a sound was produced near it, caused corresponding variations in the pressure on the carbon powder, and this produced similar variations in its electric resistance.
^ Hence, when the undulating telephonic currents were made to pass through the apparatus, the constant variation of the friction of the spring caused the deflexions of the diaphragm to vary in unison with the variation of the electric The extreme smallness of the magnets which might be successfully employed was first demonstrated by Professor Peirce of Brown University, Providence , R.I. .
^ Some earlier flip phones had a small brick-like form factor with a hinge at the bottom of the phone that was attached to a flat piece of plastic which flipped up to cover the keypad but left the display screen exposed.- MOBILE PHONES HISTORY AND DEVELOPMENT ONLINE CHEAP BEST VALUE BARGAINS AIRTIME TEXTS VIDEO MESSAGING DEALS 28 January 2010 1:30 UTC www.bluebird-electric.net [Source type: FILTERED WITH BAYES]
.^ The current from the line was made to pass through the spring and paper to the cylinder .
^ Experiments very similar to these of Edison were made by Elisha Gray of Boston, Mass., and described by him in papers communicated to the American Electrical Society in 1875 and 1878.
^ These devices have made our lives very simple for communicating.
.^ The diaphragm was itself used as the rubbing surface, and it was either mounted and rotated or the fingers were moved over it.
.^ When the current passed, the friction was felt to increase, and the effect of sending a rapidly undulating current through the arrangement was to produce a sound.
^ Hence, when the undulating telephonic currents were made to pass through the apparatus, the constant variation of the friction of the spring caused the deflexions of the diaphragm to vary in unison with the variation of the electric The extreme smallness of the magnets which might be successfully employed was first demonstrated by Professor Peirce of Brown University, Providence , R.I. .
^ The current from the battery used passed from the diaphragm through the granulated carbon to the metallic back of the box.
.^ The application of this apparatus to the transmission of music was described by Gray .'
.^ A light opera called Cupid's Telephone brought Bell's invention to Broadway -- and the silent movies embraced the talking machine right from the beginning.- American Experience . Technology . The Telephone . The Film & More | Program Transcript | PBS 11 January 2010 10:40 UTC www.pbs.org [Source type: FILTERED WITH BAYES]
^ Narrator: In the courtroom, Bell was an ideal witness: literate, poised and forceful.- Louis Galambos: Well, he brought believability.- American Experience . Technology . The Telephone . The Film & More | Program Transcript | PBS 11 January 2010 10:40 UTC www.pbs.org [Source type: FILTERED WITH BAYES]
^ Bell"): Alexander Graham Bell stands on stage with one telephone; Thomas Watson stands in a small room with another.- American Experience . Technology . The Telephone . The Film & More | Program Transcript | PBS 11 January 2010 10:40 UTC www.pbs.org [Source type: FILTERED WITH BAYES]
.^ Sir W. Thomson (Lord Kelvin) observed in 1863 3 that when a condenser is charged or discharged, a sharp click is heard, and a similar observation was made by Cromwell F. Varley, who proposed to make use of it in a telegraphic receiving instrument.4 In Dolbear's instrument one plate of a condenser was a flexible diaphragm, connected with the telephone line in such a way that the varying electric potential produced by the action of the transmitting telephone caused an increased or diminished charge in the condenser.
^ Hence, when the undulating telephonic currents were made to pass through the apparatus, the constant variation of the friction of the spring caused the deflexions of the diaphragm to vary in unison with the variation of the electric The extreme smallness of the magnets which might be successfully employed was first demonstrated by Professor Peirce of Brown University, Providence , R.I. .
^ Watson quickly constructed a new device, placing a lamb skin diaphragm opposite a magnet in a transmitter, running a connecting wire through sulfuric acid, causing the receiving membrane to vibrate.- American Experience . Technology . The Telephone . The Film & More | Program Transcript | PBS 11 January 2010 10:40 UTC www.pbs.org [Source type: FILTERED WITH BAYES]
.^ This alteration of charge caused a corresponding change in the mutual attraction of the plates of the condenser; hence the flexible plate was made to copy the vibrations of the diaphragm of the transmitter.
^ Watson quickly constructed a new device, placing a lamb skin diaphragm opposite a magnet in a transmitter, running a connecting wire through sulfuric acid, causing the receiving membrane to vibrate.- American Experience . Technology . The Telephone . The Film & More | Program Transcript | PBS 11 January 2010 10:40 UTC www.pbs.org [Source type: FILTERED WITH BAYES]
^ Sir W. Thomson (Lord Kelvin) observed in 1863 3 that when a condenser is charged or discharged, a sharp click is heard, and a similar observation was made by Cromwell F. Varley, who proposed to make use of it in a telegraphic receiving instrument.4 In Dolbear's instrument one plate of a condenser was a flexible diaphragm, connected with the telephone line in such a way that the varying electric potential produced by the action of the transmitting telephone caused an increased or diminished charge in the condenser.
.^ It is obvious that this apparatus might be used either as a transmitter or as a receiver, but that the effects must under ordinary circumstances be in either case extremely feeble.
^ The apparatus thus acted as both a transmitter and a receiver ; indeed it is essentially the magneto-receiver which has come into universal use in practical telephony, though for transmission it was soon superseded by forms of microphonic transmitters.
^ This article generally looked at how data that are deleted and that might be subsequently recovered and used as evidence may be viewed following the case of R .v.- Mobile Telephone Evidence: 11/01/2006 - 12/01/2006 11 September 2009 9:42 UTC trewmte.blogspot.com [Source type: FILTERED WITH BAYES]
.^ It was very early recognized - and, indeed, is mentioned in the first patents of Bell, and in a caveat filed by Elisha Gray in the United States patent office only some two hours after Bell's application for a patent - that sounds and spoken words might be transmitted to a distance by causing the vibrations of a diaphragm to vary the resistance in the circuit.
^ Hence, when the undulating telephonic currents were made to pass through the apparatus, the constant variation of the friction of the spring caused the deflexions of the diaphragm to vary in unison with the variation of the electric The extreme smallness of the magnets which might be successfully employed was first demonstrated by Professor Peirce of Brown University, Providence , R.I. .
^ Robert Bruce : The remarkable coincidence, as it seemed, of Elisha Gray's caveat being entered on the same day that Bell's patent application was, has raised a debate that still continues, and I think altogether unnecessarily.- American Experience . Technology . The Telephone . The Film & More | Program Transcript | PBS 11 January 2010 10:40 UTC www.pbs.org [Source type: FILTERED WITH BAYES]
.^ He proposed to introduce into the circuit a cell containing carbon powder, the pressure on which could be varied by the micro- vibrations of a diaphragm.
^ Both Bell and Gray proposed to do this by introducing a column of liquid into the circuit, the length or the resistance of which could be varied by causing the vibrations of the diaphragm to vary the depth of immersion of a light rod fixed to it and dipping into the liquid.
^ It was very early recognized - and, indeed, is mentioned in the first patents of Bell, and in a caveat filed by Elisha Gray in the United States patent office only some two hours after Bell's application for a patent - that sounds and spoken words might be transmitted to a distance by causing the vibrations of a diaphragm to vary the resistance in the circuit.
.^ This seems to have been the first transmitter in which it was proposed to use the resistance at the contact of two conductors.
^ Almost simultaneously with Berliner, Edison conceived the idea of using a variable resistance transmitter.
^ On the 4th of April 1877 Emile Berliner filed a caveat in the United States patent office, in which he stated that, on the principle of the variation with pressure of the resistance at the contact of two conductors, he had made an instrument which could be used as a telephone transmitter, and that, in consequence of the mutual forces between the two parts of the current on the two sides of the point of contact, the instrument was capable of acting as a receiver.
.^ The caveat was illustrated by a sketch showing a diaphragm with a metal patch in the See George B. Prescott, The Speaking Telephone (London, 1879), pp.
.^ Scientific American, 18th June 1881.
236.
4 See
Tel. . 1st August 1877, p.
^ Journ., 1st August 1877, p.
178, also
Adams,
Journ. Soc. Tel.
. 18 77, p.
^ Eng., 18 77, p.
476.
centre, against which a metal knob was lightly pressed by an
adjusting screw.
.^ This seems to have been the first transmitter in which it was proposed to use the resistance at the contact of two conductors.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ Almost simultaneously with Berliner, Edison conceived the idea of using a variable resistance transmitter.
.^ Almost simultaneously with Berliner, Edison conceived the idea of using a variable resistance transmitter.
^ This seems to have been the first transmitter in which it was proposed to use the resistance at the contact of two conductors.
.^ He proposed to introduce into the circuit a cell containing carbon powder, the pressure on which could be varied by the micro- vibrations of a diaphragm.
^ He sometimes held the carbon powder against the diaphragm in a small tr ans' shallow cell (from a quarter to half an inch in diameter and about an eighth of an inch deep), and sometimes he used what he describes as a fluff, that is, a little brush of silk fibre with plumbago rubbed into it.
^ Both Bell and Gray proposed to do this by introducing a column of liquid into the circuit, the length or the resistance of which could be varied by causing the vibrations of the diaphragm to vary the depth of immersion of a light rod fixed to it and dipping into the liquid.
.^ He sometimes held the carbon powder against the diaphragm in a small tr ans' shallow cell (from a quarter to half an inch in diameter and about an eighth of an inch deep), and sometimes he used what he describes as a fluff, that is, a little brush of silk fibre with plumbago rubbed into it.
^ The microphonic arrangement consisted of a spring S, about the hundredth of an inch thick and the eighth of an inch broad, fixed at one end to a lever L, and carrying at its free extremity a brass block W. In one side of W a small disk C of gas carbon was inserted, resting on the hemispherical end of a small platinum pin K, about the twentieth of an inch in diameter, held in position by a thin spring A. The pressure of the carbon on the platinum point could be adjusted by the screw N, which turned the lever about the flexible joint G. The electrical connexions of the instrument as arranged for actual use are also illustrated in the figure.
^ He proposed to introduce into the circuit a cell containing carbon powder, the pressure on which could be varied by the micro- vibrations of a diaphragm.
.^ In another form the plumbago powder was worked into a button cemented together with syrup and other substances.
.^ In it the electrodes were of platinum and carbon.
^ In the specification of the patent applied for on the list of July 1877 he showed a sketch of an instrument which consisted of a diaphragm, with a small platinum patch in the centre for an electrode, against which a hard point, made of plumbago powder cemented together with india -rubber and vulcanized, was pressed by a long spring, the pressure of the carbon against the platinum disk being adjusted by a straining screw near the base of the spring.
^ The microphonic arrangement consisted of a spring S, about the hundredth of an inch thick and the eighth of an inch broad, fixed at one end to a lever L, and carrying at its free extremity a brass block W. In one side of W a small disk C of gas carbon was inserted, resting on the hemispherical end of a small platinum pin K, about the twentieth of an inch in diameter, held in position by a thin spring A. The pressure of the carbon on the platinum point could be adjusted by the screw N, which turned the lever about the flexible joint G. The electrical connexions of the instrument as arranged for actual use are also illustrated in the figure.
.^ Subsequently he filed an application for a patent in which various forms of springs and weights assisted in maintaining the contacts and otherwise improved the instrument.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ One of the electrodes was attached to a sounding board capable of being vibrated by sound-waves and the other was held either by springs or weights in delicate contact with it.
.^ In the early part of 1878 Professor D. E. Hughes, while engaged in experiments upon a Bell telephone in an electric circuit, discovered that a peculiar noise was produced whenever two hard electrodes, such as two wires, were - drawn across each other, or were made to touch each other with a variable degree of firmness.
^ Hence, when the undulating telephonic currents were made to pass through the apparatus, the constant variation of the friction of the spring caused the deflexions of the diaphragm to vary in unison with the variation of the electric The extreme smallness of the magnets which might be successfully employed was first demonstrated by Professor Peirce of Brown University, Providence , R.I. .
^ This apparatus has two coils, one of which, connected across the line, is provided for the purpose of projecting the shutter, while the other is intended for its restoration and is joined in a local circuit arranged to be closed when a plug is inserted in any one of the associated jacks.
.^ Acting upon this discovery, he constructed an instrument which he called a " microphone," 6 and which consisted essentially of two hard carbon electrodes placed in contact, with a current passing through the point of contact and a telephone included in the same circuit.
^ The average cost of constructing an exchange circuit in the metropolitan area (including the installation of telephone instruments and of exchange apparatus, but excluding the provision of spare plant) has been £33.
^ On the 4th of April 1877 Emile Berliner filed a caveat in the United States patent office, in which he stated that, on the principle of the variation with pressure of the resistance at the contact of two conductors, he had made an instrument which could be used as a telephone transmitter, and that, in consequence of the mutual forces between the two parts of the current on the two sides of the point of contact, the instrument was capable of acting as a receiver.
.^ One of the electrodes was attached to a sounding board capable of being vibrated by sound-waves and the other was held either by springs or weights in delicate contact with it.
^ In 1831 Wheatstone by his " magic lyre " experiment showed that, when the sounding -boards of two musical instruments are connected together by a rod of pine wood, a tune played on one will be faithfully reproduced by the other.
^ When the sounding board was spoken to or subjected to sound-waves, the mechanical resistance of the loose electrode, due to its weight, or the spring, or both, served to vary the pressure at the contact, and this gave to the current a form corresponding to the sound-waves, and it was therefore capable of being used as a speaking-telephone transmitter.'
.^ One of the electrodes was attached to a sounding board capable of being vibrated by sound-waves and the other was held either by springs or weights in delicate contact with it.
^ When the sounding board was spoken to or subjected to sound-waves, the mechanical resistance of the loose electrode, due to its weight, or the spring, or both, served to vary the pressure at the contact, and this gave to the current a form corresponding to the sound-waves, and it was therefore capable of being used as a speaking-telephone transmitter.'
^ On the 4th of April 1877 Emile Berliner filed a caveat in the United States patent office, in which he stated that, on the principle of the variation with pressure of the resistance at the contact of two conductors, he had made an instrument which could be used as a telephone transmitter, and that, in consequence of the mutual forces between the two parts of the current on the two sides of the point of contact, the instrument was capable of acting as a receiver.
.^ The next transmitter of note was that introduced by Francis Blake, which came into wide use in the United States of America a.nd other countries.
^ It is widely used in America, and was introduced into Great Britain in 1907.
^ Another type of microphone which was used in Europe much more than in the United States was the multiple-contact instrument.
.^ In it the electrodes were of platinum and carbon.
To a frame F (fig. 5) was attached a diaphragm D of thin
sheet iron; in front of this was a
cover M, M provided with a suitable cavity for directing the
sound-waves against the diaphragm.
.^ The microphonic arrangement consisted of a spring S, about the hundredth of an inch thick and the eighth of an inch broad, fixed at one end to a lever L, and carrying at its free extremity a brass block W. In one side of W a small disk C of gas carbon was inserted, resting on the hemispherical end of a small platinum pin K, about the twentieth of an inch in diameter, held in position by a thin spring A. The pressure of the carbon on the platinum point could be adjusted by the screw N, which turned the lever about the flexible joint G. The electrical connexions of the instrument as arranged for actual use are also illustrated in the figure.
^ In one form a drum , mounted on an axis and covered by a band of paper soaked in a solution of caustic potash, was turned under a spring the end of which was in contact through a platinum point with the paper.
^ A washer of thin flexible mica G concentric with the carbon button is carried by the brass disk, and projecting over the edge of this is held firmly against the rim of the cylindrical wall of the case by an annular brass collar H, which is screwed upon the outer curved surface of this wall.
.^ The current from the battery passes from one of the carbon disks to the other through the particles of granulated carbon which fill the space between them.
^ The impedance coils shown connected between the battery and the lines and between the latter and the transmitters are joined up non-inductively as regards the transmitter circuits, but inductively as regards the secondary circuits.
^ The subscriber's meter is joined in multiple with the cut-off relay, and whenever a peg is connected to the circuit a current flows through the meter.
.^ This formed a local circuit at the transmitting station.
.^ The current from the line was made to pass through the spring and paper to the cylinder .
^ The line of circuit passed through the secondary of the induction coil I to the line, from that to the telephone T at the receiving station, 'See Journal of the Telegraph, New York , April 1877; Philadelphia Times, 9th July 1877; and Scientific American, August 181 This term was used by Wheatstone in 1827 for an acoustic apparatus intended to convert very feeble into audible sounds; see his Scientific Papers, p.
^ In the meantime the callinglamp has darkened; and each subscriber's line being equipped with a cut-off relay whose function it is to disconnect tl, e calling apparatus while the circuit is in use, the insertion o r a peg is immediately followed by the disappearance of the calling signal.
32.
' See
Proc. Roy. Soc., xxvii. 362;
Proc. Phys.
Soc., ii. 255;
Phil. . 5th ser., vol.
^ Mag., 3rd ser., vol.
^ Mag., 5th ser., vol.
vi. p. 44;
W. H. Preece,
Journ. Soc. Tel. Eng., vii. . and
then either to earth or back to the induction coil by a return line
of wire.
^ Gray's and then either to earth or back to the induction coil by a return line of wire.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ A single line of wire, like an ordinary telegraph line, had a Bell telephone included in it at each end, and the ends were put to earth.
.^ Two methods of " multipling " have been much used.
^ Another type of microphone which was used in Europe much more than in the United States was the multiple-contact instrument.
^ Transmitting binary or digital information today is, of course, much more complicated and faster than sending Morse code.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ In this several microphonic joints were employed.
FIG. 5. - Blake's Transmitter.
.^ Thus, in the Crossley transmitter four hard carbon pencils were arranged in a lozenge -shaped figure, the ends of each pencil resting loosely in a small carbon block.
^ In the Ader transmitter as many as twelve carbon pencils were employed, arranged in a series of two groups with six pencils in parallel in each group.
.^ These blocks were fastened to a diaphragm of wood.
.^ The circuit connexions were such that two adjacent sides of the lozenge were in parallel and two in series.
^ An improvement was effected in this respect by the introduction of the " bridging " system, in which the bells possessing high inductance are placed in parallel between the two wires of the circuit.
^ In the Ader transmitter as many as twelve carbon pencils were employed, arranged in a series of two groups with six pencils in parallel in each group.
.^ In the Ader transmitter as many as twelve carbon pencils were employed, arranged in a series of two groups with six pencils in parallel in each group.
^ The circuit connexions were such that two adjacent sides of the lozenge were in parallel and two in series.
^ Thus, in the Crossley transmitter four hard carbon pencils were arranged in a lozenge -shaped figure, the ends of each pencil resting loosely in a small carbon block.
.^ These were supported at their ends in parallel carbon bars, which were carried by a nearly horizontal wooden diaphragm.
.^ Such multiple-electrode transmitters give a loud although somewhat harsh sound, and will bear being spoken to very strongly without breaking the circuit.
^ One of the electrodes was attached to a sounding board capable of being vibrated by sound-waves and the other was held either by springs or weights in delicate contact with it.
^ We need to bear in mind diseases such as MS and Alzheimer's are linked to proteins being found in the brain."- Cell Phones 31 January 2010 13:24 UTC tuberose.com [Source type: Academic]
.^ A type of transmitter which has come to be invaluable in connexion with long distance telephony, and which has practically superseded all other forms, is the granular carbon transmitter.
^ This instrument has almost entirely displaced all other forms of transmitter.
^ The apparatus thus acted as both a transmitter and a receiver ; indeed it is essentially the magneto-receiver which has come into universal use in practical telephony, though for transmission it was soon superseded by forms of microphonic transmitters.
.^ The earliest instrument of this kind was the Hunnings transmitter, patented in 1878.
^ This was constructed of a shallow box placed in a vertical position, with metallic front and back and insulating sides.
^ The current from the battery used passed from the diaphragm through the granulated carbon to the metallic back of the box.
.^ The front face was of thin metal, and served as a diaphragm.
^ D of thin sheet iron; in front of this was a cover M, M provided with a suitable cavity for directing the sound-waves against the diaphragm.
.^ The box was filled nearly, but not quite full, of granulated hard carbon.
^ The space enclosed between the front and rear faces of the box is filled about three-quarters full of finely granulated hard carbon, which therefore lies in contact with the front and rear carbon disks of the apparatus, and also fills up the space lying between the lower edge of these disks and the curved surface of the case.
^ The front or cover of the case is a similar button of hard polished carbon D, also slightly smaller in diameter than the cylindrical wall of the box.
.^ The current from the battery used passed from the diaphragm through the granulated carbon to the metallic back of the box.
^ The current from the battery passes from one of the carbon disks to the other through the particles of granulated carbon which fill the space between them.
^ When the current passed, the friction was felt to increase, and the effect of sending a rapidly undulating current through the arrangement was to produce a sound.
.^ When spoken to the diaphragm vibrated, and thus set the carbon granules into vigorous vibration.
^ He proposed to introduce into the circuit a cell containing carbon powder, the pressure on which could be varied by the micro- vibrations of a diaphragm.
^ The current from the battery used passed from the diaphragm through the granulated carbon to the metallic back of the box.
.^ The vast number of microphonic contacts present give rise to very strong electrical undulations, and hence to a loud sound.
^ In connexion with the present subject it is important to notice the three characteristics of a musical sound, namely, pitch , loudness and quality.
^ His aim was the production, by means of the undulations of pressure on a membrane caused by sound, of an electric current the strength of which should at every instant vary directly as the pressure varied).
.^ The chief difficulty with this transmitter, and with various others of later date based upon it, has been the frequent packing of the carbon granules, which renders the instrument inoperative.
^ The motions impressed upon the carbon granules are very vigorous, and this together with the particular arrangement of the parts of the instrument is effectual in obviating the difficulty from packing which attended the use of earlier forms of granulated carbon transmitters.
^ This instrument has almost entirely displaced all other forms of transmitter.
.^ The difficulty was first satisfactorily overcome in the long-distance transmitter, invented by A. C. White in the laboratory of the American Bell Telephone Company, and commonly known as the " solid back transmitter " (fig.
^ T-mobile was the first international communications company offering service to both the US and Europe and is well known for its ad campaigns featuring Catherine Zeta Jones.- T-Mobile To Go Prepaid Cell Phones | Prepaid Reviews 28 January 2010 1:30 UTC www.prepaidreviews.com [Source type: General]
^ In 1885 there were only 3800 telephone subscribers in London and less than io,000 in the rest of the United Kingdom, and telephonic services were available in only about 75 towns, while in the same year the American Bell Telephone Company had over 134,000 subscribers.
6).
.^ The microphonic portion of the transmitter is contained in a thin cylindrical box or case of brass A, the inner curved surface of which is covered with an insulating layer of paper.
^ A washer of thin flexible mica G concentric with the carbon button is carried by the brass disk, and projecting over the edge of this is held firmly against the rim of the cylindrical wall of the case by an annular brass collar H, which is screwed upon the outer curved surface of this wall.
^ The separate wires are surrounded only with a loose covering of specially prepared paper, which furnishes abundant insulation.
.^ The case is firmly fixed to a " bridge " B with its back or bottom in a vertical position.
^ This was constructed of a shallow box placed in a vertical position, with metallic front and back and insulating sides.
.^ The front or cover of the case is a similar button of hard polished carbon D, also slightly smaller in diameter than the cylindrical wall of the box.
^ To the brass bottom of the case is attached 'a thin disk of polished hard carbon C, which is slightly less in diameter than the brass bottom, so that the carbon disk almost entirely covers this brass back, leaving only a slight annular space around its edge.
^ A washer of thin flexible mica G concentric with the carbon button is carried by the brass disk, and projecting over the edge of this is held firmly against the rim of the cylindrical wall of the case by an annular brass collar H, which is screwed upon the outer curved surface of this wall.
.^ The front or cover of the case is a similar button of hard polished carbon D, also slightly smaller in diameter than the cylindrical wall of the box.
^ A washer of thin flexible mica G concentric with the carbon button is carried by the brass disk, and projecting over the edge of this is held firmly against the rim of the cylindrical wall of the case by an annular brass collar H, which is screwed upon the outer curved surface of this wall.
^ To the brass bottom of the case is attached 'a thin disk of polished hard carbon C, which is slightly less in diameter than the brass bottom, so that the carbon disk almost entirely covers this brass back, leaving only a slight annular space around its edge.
.^ It is attached to a brass disk E, which is fastened to the centre of the diaphragm F by means of a rivet , and is capable of moving to and fro like a plunger when the diaphragm vibrates.
^ The spring was attached to the centre of a diaphragm in such a way that, when the drum was turned, the friction between the point of the spring and the paper deflected !
^ Two disks of thin metal , or two stretched membranes, each furnished with a mouthpiece , are connected together by a thin string or wire attached at each end to the centres of the membranes.
.^ A washer of thin flexible mica G concentric with the carbon button is carried by the brass disk, and projecting over the edge of this is held firmly against the rim of the cylindrical wall of the case by an annular brass collar H, which is screwed upon the outer curved surface of this wall.
^ The microphonic arrangement consisted of a spring S, about the hundredth of an inch thick and the eighth of an inch broad, fixed at one end to a lever L, and carrying at its free extremity a brass block W. In one side of W a small disk C of gas carbon was inserted, resting on the hemispherical end of a small platinum pin K, about the twentieth of an inch in diameter, held in position by a thin spring A. The pressure of the carbon on the platinum point could be adjusted by the screw N, which turned the lever about the flexible joint G. The electrical connexions of the instrument as arranged for actual use are also illustrated in the figure.
^ The microphonic portion of the transmitter is contained in a thin cylindrical box or case of brass A, the inner curved surface of which is covered with an insulating layer of paper.
.^ The box is thus entirely closed at the front, while the front carbon disk, which constitutes an electrode, is perfectly free to follow the motions of the diaphragm.
^ The front or cover of the case is a similar button of hard polished carbon D, also slightly smaller in diameter than the cylindrical wall of the box.
.^ The difficulty was first satisfactorily overcome in the long-distance transmitter, invented by A. C. White in the laboratory of the American Bell Telephone Company, and commonly known as the " solid back transmitter " (fig.
^ Solid Back Transmitter.
.^ The box was filled nearly, but not quite full, of granulated hard carbon.
^ The space enclosed between the front and rear faces of the box is filled about three-quarters full of finely granulated hard carbon, which therefore lies in contact with the front and rear carbon disks of the apparatus, and also fills up the space lying between the lower edge of these disks and the curved surface of the case.
^ A washer of thin flexible mica G concentric with the carbon button is carried by the brass disk, and projecting over the edge of this is held firmly against the rim of the cylindrical wall of the case by an annular brass collar H, which is screwed upon the outer curved surface of this wall.
.^ The current from the battery passes from one of the carbon disks to the other through the particles of granulated carbon which fill the space between them.
^ The current from the battery used passed from the diaphragm through the granulated carbon to the metallic back of the box.
^ When the current passed, the friction was felt to increase, and the effect of sending a rapidly undulating current through the arrangement was to produce a sound.
.^ The disks and granules constitute a very powerful microphone.
.^ The motions impressed upon the carbon granules are very vigorous, and this together with the particular arrangement of the parts of the instrument is effectual in obviating the difficulty from packing which attended the use of earlier forms of granulated carbon transmitters.
^ The chief difficulty with this transmitter, and with various others of later date based upon it, has been the frequent packing of the carbon granules, which renders the instrument inoperative.
^ This instrument has almost entirely displaced all other forms of transmitter.
.^ This instrument has almost entirely displaced all other forms of transmitter.
^ A type of transmitter which has come to be invaluable in connexion with long distance telephony, and which has practically superseded all other forms, is the granular carbon transmitter.
^ The chief difficulty with this transmitter, and with various others of later date based upon it, has been the frequent packing of the carbon granules, which renders the instrument inoperative.
Subscribers' Organization
.^ The employment of the telephone as one of the great means of communication requires a definite organization of the subscribers.
^ There is only one signal on the cord circuit at B, and that signal is controlled by exchange A. Each of the subscribers controls a signal at A, and when either or both of the telephones are replaced, the action is indicated by the lamps there.
^ One desirable feature of a mobile telephone system is the ability to roam; that is, subscribers must be able to call and be called in cities other than their home areas.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ It is not practicable to connect each subscriber directly to all the others, hence a system of exchanges has been adopted.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ Each subscriber's circuit is further connected to another spring-jack directly associated with the calling-drop.
.^ The territory in which a telephone administration operates is usually divided into a number of local areas, in each of which one or more exchanges are placed.
^ When the subscribers in a local area exceed a certain number, or when for some other reason it is not convenient or economical to connect all the subscribers in the area to one exchange, it is usual to divide the area into a number of districts in each of which an exchange is placed, and to connect these district exchanges together by means of " junction circuits."
^ These inter-area or long-distance lines, called trunk circuits in England , terminate at one exchange in each local area, and between that exchange and the various district exchanges junction circuits are provided for the purpose of connecting subscribers to the trunk lines.
.^ An exchange is a central station to which wires are brought from the various subscribers in its neighbourhood, any two of whom can be put in telephonic communication with each other when the proper pairs of wires are joined together in the exchange.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ A single line of wire, like an ordinary telegraph line, had a Bell telephone included in it at each end, and the ends were put to earth.
.^ These inter-area or long-distance lines, called trunk circuits in England , terminate at one exchange in each local area, and between that exchange and the various district exchanges junction circuits are provided for the purpose of connecting subscribers to the trunk lines.
^ When the subscribers in a local area exceed a certain number, or when for some other reason it is not convenient or economical to connect all the subscribers in the area to one exchange, it is usual to divide the area into a number of districts in each of which an exchange is placed, and to connect these district exchanges together by means of " junction circuits."
^ The territory in which a telephone administration operates is usually divided into a number of local areas, in each of which one or more exchanges are placed.
.^ In some cases the exchanges are connected together directly; but when the volume of traffic is not sufficient to warrant the adoption of such a course connexions between two exchanges are made through junction centres to which both are connected.
^ Sporting both 2.7- and 1.7-inch screens, the phone offers tri-band GSM connectivity, two megapixel camera, and GPS. HTC Touch Pro -- Jun.- The Windows Mobile Phones Showcase - Windows For Devices Articles - Windows for Devices 28 January 2010 1:30 UTC www.windowsfordevices.com [Source type: General]
^ The circuit connexions were such that two adjacent sides of the lozenge were in parallel and two in series.
.^ A system of wires, similar to that which connects the district exchanges in an area, links together the various local areas in the territory, and sometimes the territory of one administration with that of another.
^ These inter-area or long-distance lines, called trunk circuits in England , terminate at one exchange in each local area, and between that exchange and the various district exchanges junction circuits are provided for the purpose of connecting subscribers to the trunk lines.
^ When the subscribers in a local area exceed a certain number, or when for some other reason it is not convenient or economical to connect all the subscribers in the area to one exchange, it is usual to divide the area into a number of districts in each of which an exchange is placed, and to connect these district exchanges together by means of " junction circuits."
.^ These inter-area or long-distance lines, called trunk circuits in England , terminate at one exchange in each local area, and between that exchange and the various district exchanges junction circuits are provided for the purpose of connecting subscribers to the trunk lines.
^ These areas are called cells.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ During the progress of these operations the A operator connects the originating subscriber to the junction circuit named by the B operator.
Circuit and Working Arrangements
.^ The method first employed for working a telephone line was extremely simple.
^ The Hush-A-Phone was a simple product that slipped over a Candlestick Phone or Telephone Handset and gave the user some privacy (the first noise canceling microphone!- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ As no practical process of telephone relaying has been devised, it is extremely important that the character of the line should be such as to favour the preservation of the strength and form of the telephone current.
.^ A single line of wire, like an ordinary telegraph line, had a Bell telephone included in it at each end, and the ends were put to earth.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ The telephone was switched out of circuit when not in use and the bell put in its place, a key being used for throwing the battery into circuit to make the signal .
.^ Words spoken to the telephone at one end could be heard by holding the telephone to the ear at the other.
^ The radios were half-duplex, this is to say, you could talk or listen, one or the other.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ One desirable feature of a mobile telephone system is the ability to roam; that is, subscribers must be able to call and be called in cities other than their home areas.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ To obviate the inconvenience of placing the telephone to the mouth and the ear alternately, two telephones were commonly used at each end, joined either parallel to each other or in series.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ The telephone was switched out of circuit when not in use and the bell put in its place, a key being used for throwing the battery into circuit to make the signal .
.^ Works for phones, texting, or just generally not paying attention to the multi-ton machine you're controlling while it hurtles down the road.- Slashdot | The Cell Phone Has Changed — New Etiquette Needed 31 January 2010 13:24 UTC slashdot.org [Source type: FILTERED WITH BAYES]
.^ The telephone was switched out of circuit when not in use and the bell put in its place, a key being used for throwing the battery into circuit to make the signal .
^ In the meantime the callinglamp has darkened; and each subscriber's line being equipped with a cut-off relay whose function it is to disconnect tl, e calling apparatus while the circuit is in use, the insertion o r a peg is immediately followed by the disappearance of the calling signal.
^ Landline telegraphs used a key to make or break an electrical circuit, a battery to produce power, a single line joining one telegraph station to another and an electromagnetic receiver or sounder that upon being turned on and off, produced a clicking noise.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ This arrangement is still employed, a hook being attached to the switch lever so that the mere hanging up of the telephone puts the bell in circuit.
^ A single line of wire, like an ordinary telegraph line, had a Bell telephone included in it at each end, and the ends were put to earth.
^ The telephone was switched out of circuit when not in use and the bell put in its place, a key being used for throwing the battery into circuit to make the signal .
.^ In some cases when a magneto-generator is employed for calling purposes the coil of the machine is automatically cut out of circuit when it is not in action, and is brought into circuit when the handle is turned by the operation of a centrifugal or other arrangement.
^ Though many types of manually operated switchboards have been brought into use, differing from each other in respect of circuit and working arrangements, yet each of them may be placed in one or other of three main classes according as the system of working is magneto, call-wire, or common battery.
^ This apparatus has two coils, one of which, connected across the line, is provided for the purpose of projecting the shutter, while the other is intended for its restoration and is joined in a local circuit arranged to be closed when a plug is inserted in any one of the associated jacks.
.^ At first it was usual to join the microphone transmitter in the direct circuit.
^ The impedance coils shown connected between the battery and the lines and between the latter and the transmitters are joined up non-inductively as regards the transmitter circuits, but inductively as regards the secondary circuits.
.^ It was soon found that it could only be used to advantage in this way when the total resistance of the circuit, exclusive of the microphone, was small compared with the resistance of the microphone - that is, on very short lines worked with FIG. 7.
^ Oliver Heaviside showed mathematically that uniformly-distributed inductance in a telephone line would diminish both attenuation and distortion, and that if the inductance were great enough and the insulation resistance not too high the circuit would be distortionless, while currents of all frequencies would be equally attenuated.
^ The resistance of the microphone can thus be made a large fraction of the total resistance of the circuit in which it is placed; hence by using considerable currents, small variations in its resistance can be made to induce somewhat powerful currents in the line wire.
low resistance telephones.
.^ The transmitter on long and high resistance lines worked better by joining, in the manner shown in fig.
^ It was soon found that it could only be used to advantage in this way when the total resistance of the circuit, exclusive of the microphone, was small compared with the resistance of the microphone - that is, on very short lines worked with FIG. 7.
^ The impedance coils shown connected between the battery and the lines and between the latter and the transmitters are joined up non-inductively as regards the transmitter circuits, but inductively as regards the secondary circuits.
.^ The impedance coils shown connected between the battery and the lines and between the latter and the transmitters are joined up non-inductively as regards the transmitter circuits, but inductively as regards the secondary circuits.
^ The transmitter is placed in multiple with the primary winding of an induction coil whose secondary operates in the loop circuit, and consequently when the transmitter is spoken into, a variable E.M.F. is impressed upon the circuit through the medium of the induction coil.
^ This apparatus has two coils, one of which, connected across the line, is provided for the purpose of projecting the shutter, while the other is intended for its restoration and is joined in a local circuit arranged to be closed when a plug is inserted in any one of the associated jacks.
.^ The resistance of the microphone can thus be made a large fraction of the total resistance of the circuit in which it is placed; hence by using considerable currents, small variations in its resistance can be made to induce somewhat powerful currents in the line wire.
^ Hence, when the undulating telephonic currents were made to pass through the apparatus, the constant variation of the friction of the spring caused the deflexions of the diaphragm to vary in unison with the variation of the electric The extreme smallness of the magnets which might be successfully employed was first demonstrated by Professor Peirce of Brown University, Providence , R.I. .
^ Oliver Heaviside showed mathematically that uniformly-distributed inductance in a telephone line would diminish both attenuation and distortion, and that if the inductance were great enough and the insulation resistance not too high the circuit would be distortionless, while currents of all frequencies would be equally attenuated.
.^ The requisite energy is derived from the battery.
.^ In the earliest telephone switchboards the lines were connected to vertical conducting strips, across which were placed a series of similar horizontal strips in such a manner that any horizontal could be connected to any line strip by the insertion of a plug into holes provided in the strips for the purpose.
^ Any two lines could be connected together by connecting both to the same horizontal strip.
^ Various states already have such laws in place, as well as certain cities across the country.
.^ Any two lines could be connected together by connecting both to the same horizontal strip.
^ Sporting both 2.7- and 1.7-inch screens, the phone offers tri-band GSM connectivity, two megapixel camera, and GPS. HTC Touch Pro -- Jun.- The Windows Mobile Phones Showcase - Windows For Devices Articles - Windows for Devices 28 January 2010 1:30 UTC www.windowsfordevices.com [Source type: General]
^ In some cases the exchanges are connected together directly; but when the volume of traffic is not sufficient to warrant the adoption of such a course connexions between two exchanges are made through junction centres to which both are connected.
.^ The next step of importance was the introduction of what was termed the " Standard board."
.^ Interesting Switchboard with only two positions with cords, but a third position with jacks for subscribers on the far right (used by right set of cords).- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ Click for a bigger photo of the Drops (used for incoming calls instead of a lamp), and connections on the Magneto Test Desk .- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ In the beginning, you couldn't even call someone who was a subscriber in the competing system, since the lines didn't connect anywhere.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
.^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ As subscribers' lines are invariably short, the smallest gauge of wire possessing the mechanical strength necessary to withstand the stresses to which it may be subjected can be employed, and bronze wire weighing 40 lb per mile is commonly used.
^ In the meantime the callinglamp has darkened; and each subscriber's line being equipped with a cut-off relay whose function it is to disconnect tl, e calling apparatus while the circuit is in use, the insertion o r a peg is immediately followed by the disappearance of the calling signal.
.^ When a plug was inserted in the spring-jack the connexion between the springs was opened, disconnecting the calling-drop from the line.
^ This apparatus has two coils, one of which, connected across the line, is provided for the purpose of projecting the shutter, while the other is intended for its restoration and is joined in a local circuit arranged to be closed when a plug is inserted in any one of the associated jacks.
^ This attracted the attention of the attendant, who in response to the call inserted a plug into the spring-jack and connected the speaking apparatus to the circuit by means of the key.
.^ Each connecting- cord circuit had associated with it a clearing-out drop connected between the cord and earth and a key by means of which the operator's speaking and ringing apparatus could be brought into circuit.
^ In the first place it increased the visibility of the signalling instrument; in the second place it brought that instrument into the position in which it could most readily catch the operator's eye; and finally it eliminated the effort involved in associating one piece of apparatus with another and in finding that other.
^ This attracted the attention of the attendant, who in response to the call inserted a plug into the spring-jack and connected the speaking apparatus to the circuit by means of the key.
.^ When a subscriber called (by turning the handle of his magneto- 'generator), the shutter of the annunciator associated with his line dropped.
^ The callingdrop of the magneto system was displaced by a relay and a small electric incandescent lamp , and whereas in the older system the calling-drop and the answering jack with which it was associated were some distance apart, the calling-lamp and the answering jack of the newer system were placed in juxtaposition.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
.^ This attracted the attention of the attendant, who in response to the call inserted a plug into the spring-jack and connected the speaking apparatus to the circuit by means of the key.
^ The operator, whose attention is thus attracted, inserts a peg in the jack, then throws over the speaking key of the cord circuit, and having ascertained particulars of the requirement places the other peg of the pair in the nearest multiple jack of the wanted subscriber, whom she proceeds to ring up.
^ Each connecting- cord circuit had associated with it a clearing-out drop connected between the cord and earth and a key by means of which the operator's speaking and ringing apparatus could be brought into circuit.
.^ Then, having obtained particulars of the subscriber's requirement, the operator connected the second plug to the spring-jack of the wanted subscriber, whom she rang up.
^ The operator, whose attention is thus attracted, inserts a peg in the jack, then throws over the speaking key of the cord circuit, and having ascertained particulars of the requirement places the other peg of the pair in the nearest multiple jack of the wanted subscriber, whom she proceeds to ring up.
^ The supervisory lamp associated with the peg in the wanted subscriber's jack glows from the time that the peg is inserted until the subscriber responds, when it darkens, in which condition it remains until the subscriber restores the receiver to the hook and causes the lamp to light up again.
When. the conversation was finished
either of the subscribers could release the shutter of the
clearing-out drop by turning his generator handle, and the operator
thus notified of the fact removed the plugs and discontinued the
connexion.
.^ The single-wire earthed circuits used in the early days of telephony were subject to serious disturbances from the induction caused by currents in neighbouring telegraph and electric light wires, and from the varying potential of the earth due to natural or artificial causes.
^ It was early recognized that a complete metallic circuit would obviate troubles from varying earth potentials, and that if the outgoing and incoming branches of the circuit were parallel and kept, by transposition spiralling, or otherwise, at equal average distances from the disturbing wire, induction effects would likewise be removed.
^ Landline telegraphs used a key to make or break an electrical circuit, a battery to produce power, a single line joining one telegraph station to another and an electromagnetic receiver or sounder that upon being turned on and off, produced a clicking noise.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ The introduction of electric tramways caused an enormous increase in disturbances of this class.
.^ It was early recognized that a complete metallic circuit would obviate troubles from varying earth potentials, and that if the outgoing and incoming branches of the circuit were parallel and kept, by transposition spiralling, or otherwise, at equal average distances from the disturbing wire, induction effects would likewise be removed.
^ After the withdrawal of the restriction against the companies erecting trunk wires it became evident that the development of the telephone services throughout the country would be facilitated by complete intercommunication and uniformity of systems, and that economies could be effected by concentration of management.
^ The single-wire earthed circuits used in the early days of telephony were subject to serious disturbances from the induction caused by currents in neighbouring telegraph and electric light wires, and from the varying potential of the earth due to natural or artificial causes.
These advantages led to the gradual supersession of the
single-wire system until at the present day the all-metallic system
is employed almost universally. Since the time when the system
first became prominent all switchboards have been arranged for
metallic circuits.
.^ The " call-wire " system has been used to some extent, but it is now obsolete.
^ Each subscriber was given the exclusive use of a circuit as in other systems, and shared a call-wire with a number of other subscribers.
^ Though many types of manually operated switchboards have been brought into use, differing from each other in respect of circuit and working arrangements, yet each of them may be placed in one or other of three main classes according as the system of working is magneto, call-wire, or common battery.
.^ The fundamental principle of the magneto system has been described in connexion with the " Standard board."
.^ In a large exchange a number of operators are necessary to attend to calls.
^ The feature of the system was the provision of special service circuits, termed call-wires, for purposes of communication between the subscribers and the exchange operators.
^ In large towns served by a number of exchanges the junction equipment is an important feature.
.^ Several single switchboards like that described may be employed, each devoted to a certain section of the subscribers, and placed in care of an operator.
^ As we've discussed, TDMA or time division multiple access, places several calls on a single frequency.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ May 19, 2006 at 5:52 am *On the internet, people can pretend to be anything they want to… like a Strand employ, as someone else already mentioned.- Cell Phone Symphony « Improv Everywhere 31 January 2010 13:24 UTC improveverywhere.com [Source type: General]
.^ In time division multiple access we separate calls by time, one after another.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ In these circumstances, when, as frequently will be the case, the person calling desires to be put in communication with a subscriber who belongs to another section, connexions must be established in the office between the two sections; this necessitates additional switchboard arrangements, and also increases the time required to put subscribers in communication with one another.
^ Hence this operator, when signalled in the ordinary way, can put any one of these subscribers in connexion with any subscriber whatever, without the necessity of calling upon another operator to make connexions.
.^ The difficulty was obviated by the introduction of the " multiple switchboard."
.^ When there were multiple positions that weren't covered by operators (like at night), an operator could use a plug from her switchboard in a jack of one on either side.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
.^ Interesting Switchboard with only two positions with cords, but a third position with jacks for subscribers on the far right (used by right set of cords).- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ Africa showed the greatest increase, and more than two-thirds of all cell phone subscribers now come from developing countries.- Cell Phones 31 January 2010 13:24 UTC tuberose.com [Source type: Academic]
^ When businesses began installing multiple phones within their buildings, an on-site switchboard was used to connect a particular phone to an outside line.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
.^ Click for a bigger photo of the Drops (used for incoming calls instead of a lamp), and connections on the Magneto Test Desk .- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ In the beginning, you couldn't even call someone who was a subscriber in the competing system, since the lines didn't connect anywhere.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ The plugs, combined with their associated switches, were what actually rang and connected telephones (the jacks).- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
.^ These springjacks, known as answering jacks, are distributed along the switchboard, a certain number being terminated upon each position and placed in the care of the operator assigned to that position.
^ These supervisory signals took the form of lamps and were placed on the keyboard in positions immediately adjacent to the associated cords.
^ When the subscribers in a local area exceed a certain number, or when for some other reason it is not convenient or economical to connect all the subscribers in the area to one exchange, it is usual to divide the area into a number of districts in each of which an exchange is placed, and to connect these district exchanges together by means of " junction circuits."
.^ Hence this operator, when signalled in the ordinary way, can put any one of these subscribers in connexion with any subscriber whatever, without the necessity of calling upon another operator to make connexions.
^ In these circumstances, when, as frequently will be the case, the person calling desires to be put in communication with a subscriber who belongs to another section, connexions must be established in the office between the two sections; this necessitates additional switchboard arrangements, and also increases the time required to put subscribers in communication with one another.
^ The system of the British Post Office is worked as follows: A subscriber desiring a long-distance connexion calls up his local exchange in the ordinary way, and the operator there, being informed that a trunk connexion is desired, extends the subscriber's line to the Post Office by means of a record circuit.
.^ Two methods of " multipling " have been much used.
^ Another type of microphone which was used in Europe much more than in the United States was the multiple-contact instrument.
^ Another access method is code division multiple access or CDMA. The cellular system that uses it, IS-95, tags each and every part of multiple conversations with a specific digital code.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Each subscriber's circuit is further connected to another spring-jack directly associated with the calling-drop.
^ This arrangement permits particulars of calls to be passed over lines while conversations are in progress.
^ In this arrangement, instead of the circuit being made through the jacks in series, each jack is connected to an independent branch from the main circuit.
.^ This arrangement is liable to give trouble, as disconnexions may arise in the spring-jacks in consequence of the failures of the springs to make contact.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ In the arrangement first introduced the line wire is connected in series through the various spring-jacks, the circuit finally passing through the answering jack to the calling-drop.
.^ Operating mistakes also cause interruptions to conversations, as it is possible, by the insertion of a plug in a multiple jack, to disconnect the circuit between two talking subscribers.
^ In the meantime the callinglamp has darkened; and each subscriber's line being equipped with a cut-off relay whose function it is to disconnect tl, e calling apparatus while the circuit is in use, the insertion o r a peg is immediately followed by the disappearance of the calling signal.
^ The call is controlled by the trunk operators, the junction circuits being equipped in such a manner that the subscribers' signals appear at the trunk exchanges, from which point disconnecting signals are sent automatically to the local exchanges, when the connexions between the trunk and the junction circuits are removed.
.^ To overcome these difficulties the " branching multiple " was introduced.
^ With the " branching multiple " the " selfrestoring drop " was introduced.
In this arrangement, instead of the
circuit being made through the jacks in series, each jack is
connected to an independent branch from the main circuit.
.^ To overcome these difficulties the " branching multiple " was introduced.
^ With the " branching multiple " the " selfrestoring drop " was introduced.
.^ This apparatus has two coils, one of which, connected across the line, is provided for the purpose of projecting the shutter, while the other is intended for its restoration and is joined in a local circuit arranged to be closed when a plug is inserted in any one of the associated jacks.
^ In 1831 Wheatstone by his " magic lyre " experiment showed that, when the sounding -boards of two musical instruments are connected together by a rod of pine wood, a tune played on one will be faithfully reproduced by the other.
^ These inter-area or long-distance lines, called trunk circuits in England , terminate at one exchange in each local area, and between that exchange and the various district exchanges junction circuits are provided for the purpose of connecting subscribers to the trunk lines.
.^ It is necessary that the operators working at a multiple board shall be able to ascertain without entering a subscriber's circuit whether the circuit be disengaged.
^ Operating mistakes also cause interruptions to conversations, as it is possible, by the insertion of a plug in a multiple jack, to disconnect the circuit between two talking subscribers.
^ Each subscriber's circuit on this system terminates upon the incoming portion of a selector switch, called a first selector, and is multipled upon the outgoing portions of a number of similar switches called connector switches.
.^ This requirement is usually met by connecting a third or " test " wire to each of the jacks associated with a subscriber's line, and by making the circuit arrangements such that this wire is either disconnected or at earth potential when the line is not in use, and at some potential above or below that of the earth, when the circuit is engaged.
^ In addition to its durability, the writer has found that this type of clip is in some respects a great deal more convenient to rise than the "suspender clip" frequently furnished with the test sets for making attachment to wires.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ As subscribers' lines are invariably short, the smallest gauge of wire possessing the mechanical strength necessary to withstand the stresses to which it may be subjected can be employed, and bronze wire weighing 40 lb per mile is commonly used.
.^ With a proper arrangement of the operator's speaking set it is possible, by touching the socket of a jack with the tip of a peg or a special " test " thimble , to determine whether the circuit connected to the jack is in use.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ Each subscriber's circuit is further connected to another spring-jack directly associated with the calling-drop.
.^ Both the series and the branching methods of multipling are recognized at the present time as standard methods, although the former is only employed in comparatively small exchanges.
^ In consequence of their high capacity, the attenuation constant of submarine cables is high, and only a small number of cables, of comparatively short length, are in use for telephonic purposes.
^ Although called 'multiple access', it is really another multiplexing method, a way to put many calls at once on a single channel.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ The magneto system itself is dying out.
.^ There are still many magneto exchanges in existence, but when new exchanges are erected only the very smallest are equipped for magneto working, that system having succumbed to the common battery one in the case of all equipments of moderate and large dimensions.
^ Though many types of manually operated switchboards have been brought into use, differing from each other in respect of circuit and working arrangements, yet each of them may be placed in one or other of three main classes according as the system of working is magneto, call-wire, or common battery.
^ Hull and Portsmouth were the only municipal telephone systems working in 1907.
.^ The " call-wire " system has been used to some extent, but it is now obsolete.
^ Each subscriber was given the exclusive use of a circuit as in other systems, and shared a call-wire with a number of other subscribers.
^ The feature of the system was the provision of special service circuits, termed call-wires, for purposes of communication between the subscribers and the exchange operators.
.^ The feature of the system was the provision of special service circuits, termed call-wires, for purposes of communication between the subscribers and the exchange operators.
^ These inter-area or long-distance lines, called trunk circuits in England , terminate at one exchange in each local area, and between that exchange and the various district exchanges junction circuits are provided for the purpose of connecting subscribers to the trunk lines.
^ The system of the British Post Office is worked as follows: A subscriber desiring a long-distance connexion calls up his local exchange in the ordinary way, and the operator there, being informed that a trunk connexion is desired, extends the subscriber's line to the Post Office by means of a record circuit.
.^ The " call-wire " system has been used to some extent, but it is now obsolete.
^ Each subscriber was given the exclusive use of a circuit as in other systems, and shared a call-wire with a number of other subscribers.
^ In the meantime the callinglamp has darkened; and each subscriber's line being equipped with a cut-off relay whose function it is to disconnect tl, e calling apparatus while the circuit is in use, the insertion o r a peg is immediately followed by the disappearance of the calling signal.
.^ Each telephone set was equipped with a special key or switch by means of which the telephone could be transferred from an exclusive line to the call-wire at will.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ A single line of wire, like an ordinary telegraph line, had a Bell telephone included in it at each end, and the ends were put to earth.
.^ A subscriber desiring a connexion pressed the key and communicated his own number and that of the wanted subscriber to the operator in attendance on the call-wire.
^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ Each subscriber's circuit on this system terminates upon the incoming portion of a selector switch, called a first selector, and is multipled upon the outgoing portions of a number of similar switches called connector switches.
.^ Then, when the connexion was made, the originating subscriber rang up the other.
^ Then, having obtained particulars of the subscriber's requirement, the operator connected the second plug to the spring-jack of the wanted subscriber, whom she rang up.
^ At the close of a conversation the originating subscriber again entered the call-wire and requested the operator to take down the connexion.
.^ At the close of a conversation the originating subscriber again entered the call-wire and requested the operator to take down the connexion.
^ During the progress of these operations the A operator connects the originating subscriber to the junction circuit named by the B operator.
^ The call is controlled by the trunk operators, the junction circuits being equipped in such a manner that the subscribers' signals appear at the trunk exchanges, from which point disconnecting signals are sent automatically to the local exchanges, when the connexions between the trunk and the junction circuits are removed.
.^ The call-wires were usually equipped with drops in order that the exchange might be called at night when the operators were not listening continuously.
^ The feature of the system was the provision of special service circuits, termed call-wires, for purposes of communication between the subscribers and the exchange operators.
^ Each telephone set was equipped with a special key or switch by means of which the telephone could be transferred from an exclusive line to the call-wire at will.
.^ One of the greatest advances made in the development of the art of telephony was the introduction of the " common battery relay system."
^ There are still many magneto exchanges in existence, but when new exchanges are erected only the very smallest are equipped for magneto working, that system having succumbed to the common battery one in the case of all equipments of moderate and large dimensions.
^ Stone Common Battery System.
.^ This advance did not merely remove the primary batteries from the subscribers' stations; it removed also the magneto-generator, and at the same time it modified considerably the conditions governing the exchange operating.
^ The feature of the system was the provision of special service circuits, termed call-wires, for purposes of communication between the subscribers and the exchange operators.
^ The record operator then removes her speaking apparatus from the circuit, and the local operator, receiving a disconnect signal, severs the connexion at the local exchange.
.^ The callingdrop of the magneto system was displaced by a relay and a small electric incandescent lamp , and whereas in the older system the calling-drop and the answering jack with which it was associated were some distance apart, the calling-lamp and the answering jack of the newer system were placed in juxtaposition.
^ Each subscriber's circuit is further connected to another spring-jack directly associated with the calling-drop.
^ When a plug was inserted in the spring-jack the connexion between the springs was opened, disconnecting the calling-drop from the line.
.^ This alteration improved the operating conditions in three ways.
.^ In the first place it increased the visibility of the signalling instrument; in the second place it brought that instrument into the position in which it could most readily catch the operator's eye; and finally it eliminated the effort involved in associating one piece of apparatus with another and in finding that other.
^ Each connexion involves the use of three switches, viz., a first selector, a connector switch, and a second selector which is brought into operation between the other two.
^ This apparatus has two coils, one of which, connected across the line, is provided for the purpose of projecting the shutter, while the other is intended for its restoration and is joined in a local circuit arranged to be closed when a plug is inserted in any one of the associated jacks.
.^ Moreover the clearing-out drop of the cord circuit was replaced by an arrangement which included the provision of one signal to be controlled through the agency of a relay by the calling subscriber, and another to be controlled by the person wanted.
^ In the meantime the callinglamp has darkened; and each subscriber's line being equipped with a cut-off relay whose function it is to disconnect tl, e calling apparatus while the circuit is in use, the insertion o r a peg is immediately followed by the disappearance of the calling signal.
^ There is only one signal on the cord circuit at B, and that signal is controlled by exchange A. Each of the subscribers controls a signal at A, and when either or both of the telephones are replaced, the action is indicated by the lamps there.
.^ These supervisory signals took the form of lamps and were placed on the keyboard in positions immediately adjacent to the associated cords.
^ There is only one signal on the cord circuit at B, and that signal is controlled by exchange A. Each of the subscribers controls a signal at A, and when either or both of the telephones are replaced, the action is indicated by the lamps there.
^ These springjacks, known as answering jacks, are distributed along the switchboard, a certain number being terminated upon each position and placed in the care of the operator assigned to that position.
.^ With the adoption of relays the signalling between the subscribers and the exchange became automatic, and, with the introduction of the principle of double and automatic supervision on the cord circuits, it became possible for the operators to tell at any instant the state of a connexion.
^ In the meantime the callinglamp has darkened; and each subscriber's line being equipped with a cut-off relay whose function it is to disconnect tl, e calling apparatus while the circuit is in use, the insertion o r a peg is immediately followed by the disappearance of the calling signal.
^ The call is controlled by the trunk operators, the junction circuits being equipped in such a manner that the subscribers' signals appear at the trunk exchanges, from which point disconnecting signals are sent automatically to the local exchanges, when the connexions between the trunk and the junction circuits are removed.
.^ As a result the time occupied by an operator per call was reduced from 50.77 seconds to 16.63 seconds.
^ But you can go through their operator and pay three times the cost of a normal call if you like.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ As the Cellular Development group puts it, "A CDMA call starts with a standard rate of 9600 bits per second (9.6 kilobits per second).- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Threefundamental common battery transmissionsystemshavebeen devised and are shown in figs.
.^ In the Hayes system (fig.
.^ In the meantime the callinglamp has darkened; and each subscriber's line being equipped with a cut-off relay whose function it is to disconnect tl, e calling apparatus while the circuit is in use, the insertion o r a peg is immediately followed by the disappearance of the calling signal.
^ In 1831 Wheatstone by his " magic lyre " experiment showed that, when the sounding -boards of two musical instruments are connected together by a rod of pine wood, a tune played on one will be faithfully reproduced by the other.
^ When the subscribers in a local area exceed a certain number, or when for some other reason it is not convenient or economical to connect all the subscribers in the area to one exchange, it is usual to divide the area into a number of districts in each of which an exchange is placed, and to connect these district exchanges together by means of " junction circuits."
.^ Threefundamental common battery transmissionsystemshavebeen devised and are shown in figs.
^ There are still many magneto exchanges in existence, but when new exchanges are erected only the very smallest are equipped for magneto working, that system having succumbed to the common battery one in the case of all equipments of moderate and large dimensions.
^ The Post Office at the same time established several telephone exchanges in provincial towns so as to enable the PostmasterGeneral " to negotiate with the telephone companies in a satisfactory manner for licences."
.^ The Stone system (fig.
.^ This allocation is split equally between wire-line and radio common carriers (each is allocated 333 channels).- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ A small snap with saw-tooth jaws frequently catches when the lineman is climbing between the wires, or when being removed from the line, and causes annoyance.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
.^ The Stone system (fig.
^ When one of two subscribers connected together by this arrangement talks, the Exchange From the Post Office Electrical Engineers' Journal.
^ In 1831 Wheatstone by his " magic lyre " experiment showed that, when the sounding -boards of two musical instruments are connected together by a rod of pine wood, a tune played on one will be faithfully reproduced by the other.
variation in resistance of the transmitter spoken into causes a
variation of the pressure at the line terminals of the impedance
coils, and since those terminals are common to the two circuits the
variable E.M.F. operates in the line of the listening subscriber,
causing the reproduction of the speech in the latter's receiver.
The Stone system, compared with that of Hayes, possesses the
Exchanc 1.
Missing image
Telephone-5.jpg
.^ Exchange From the Post Office Electrical Engineers' Journal.
^ From the Post Office Electrical Engineers' Journal.
^ When one of two subscribers connected together by this arrangement talks, the Exchange From the Post Office Electrical Engineers' Journal.
-
Dean
Common Battery System.
Missing image
Telephone-6.jpg
Missing image
Telephone-7.jpg
Missing image
Telephone-8.jpg
Missing image
Telephone-9.jpg
Missing image
Telephone-10.jpg
disadvantage that one of the conditions affecting the supply of
current to any particular subscriber's circuit is the resistance of
the
.^ Missing image Telephone-6.jpg Missing image Telephone-7.jpg Missing image Telephone-8.jpg Missing image Telephone-9.jpg Missing image Telephone-10.jpg disadvantage that one of the conditions affecting the supply of current to any particular subscriber's circuit is the resistance of the Subscriber'S Office c FIG. 1 i.
-
.^ Each subscriber was given the exclusive use of a circuit as in other systems, and shared a call-wire with a number of other subscribers.
^ The feature of the system was the provision of special service circuits, termed call-wires, for purposes of communication between the subscribers and the exchange operators.
^ Dean Common Battery System.
other circuit to which it is connected for the time being.
.^ An improvement in this respect has been effected by the insertion of condensers in the cord circuits, coupled with the use of two sets of impedance coils, one set on each.
^ A cord circuit, similar in many respects, including the method .y.^9 Jr '' of operation, but equipped with condensers and impedance coils, in place of the repeating coil, is shown in fig.
^ This apparatus has two coils, one of which, connected across the line, is provided for the purpose of projecting the shutter, while the other is intended for its restoration and is joined in a local circuit arranged to be closed when a plug is inserted in any one of the associated jacks.
side of the condensers.
Missing image
Telephone-11.jpg
.^ Missing image Telephone-11.jpg Dean's method (fig.
.^ The spring- jack used was a form of switch with two contact springs which pressed against each other, one being connected to the subscriber's line wire and the other to the annunciator, which was also earthed.
^ The impedance coils shown connected between the battery and the lines and between the latter and the transmitters are joined up non-inductively as regards the transmitter circuits, but inductively as regards the secondary circuits.
^ Each subscriber was given the exclusive use of a circuit as in other systems, and shared a call-wire with a number of other subscribers.
An earth return is used. The transmitter
is placed in multiple with the primary winding of an induction coil
whose secondary operates in the loop circuit, and consequently when
the transmitter is spoken into, a variable E.M.F. is impressed upon
the circuit through the medium of the induction coil.
.^ You MUST connect a .47mf 100V non-polar capacitor in-series with this lamp (we also stock these), or it will answer the line by itself!- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
Figs.
.^ Switchboards were originally located at telephone company Central Offices, and were used to connect subscribers together so they could talk.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
.^ The base station serving your call sends a hand-off request to the mobile switch after your signal drops below a handover threshold.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Landline telegraphs used a key to make or break an electrical circuit, a battery to produce power, a single line joining one telegraph station to another and an electromagnetic receiver or sounder that upon being turned on and off, produced a clicking noise.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ When there were multiple positions that weren't covered by operators (like at night), an operator could use a plug from her switchboard in a jack of one on either side.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ "Talk/Monitor" switch in the unit, and put in a modern T-1 transmitter and U-1 receiver.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
.^ This lamp is neat, because it will light when the line is ringing.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ When used for Message Waiting, the lamp also lights when the line is ringing.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ I wrote in passing about how increasing call capacity was the chief benefit of TDMA to cellular operators.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Interesting Switchboard with only two positions with cords, but a third position with jacks for subscribers on the far right (used by right set of cords).- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ A telegraph key tap broke the circuit momentarily, transmitting a short pulse to a distant sounder, interpreted by an operator as a dot.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ When there were multiple positions that weren't covered by operators (like at night), an operator could use a plug from her switchboard in a jack of one on either side.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
.^ Landline telegraphs used a key to make or break an electrical circuit, a battery to produce power, a single line joining one telegraph station to another and an electromagnetic receiver or sounder that upon being turned on and off, produced a clicking noise.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ In addition to channel assignment, other MTSO functions include maintaining a list of busy (that is, off-hook) mobile units and paging mobile units for which incoming calls are intended.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Even so, there are still some crackpots using this type of phone system (or Centrex) with single line phones, and they just tell you to "Call back if I cut you off while transferring you."- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
The supervisory lamp
associated with the peg in the wanted subscriber's jack glows from
the time that the peg is inserted until the subscriber responds,
when it darkens, in which condition it remains until the subscriber
restores the receiver to the hook and causes the lamp to light up
again.
.^ All in all, I’m looking for opinions from users who use their cell provider for things similar to my uses.
^ In addition to channel assignment, other MTSO functions include maintaining a list of busy (that is, off-hook) mobile units and paging mobile units for which incoming calls are intended.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Once at the receiver the equipment identifies the call, separates its pieces from the spreading code and other calls, and returns the signal back to its original 9600 bit rate.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
When both lamps glow, the operator, who
thereby knows that both subscribers have restored their
instruments, discontinues the connexion.
A cord circuit, similar in many respects, including the method
.y.^9 Jr '' of operation, but
equipped with condensers and impedance coils, in place of the
repeating coil, is shown in fig. 13.
In fig. 11 a meter or
counter is shown associated with the
subscriber's line, and in both figs. 12 and 13 position meters are
shown connected to the cord circuits. The operation of these meters
is controlled by the operators. The subscriber's meter is joined in
multiple with the cut-off relay, and whenever a peg is connected to
the circuit a current flows through the meter. This current is
small, however, and the meter is not operated until a much larger
current is passed through it.
.^ Kit inlcudes 9V batteries and snaps to connect to the battery connector inthe Kick Meter .- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
.^ When used for line sharing, put a fax on one port and all incoming calls will go to the fax, while the fax will use the next available line for outgoing calls.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
.^ Qualcomm's CDMA system uses some very advanced speech compression techniques, utilizing a variable rate vocoder, a speech synthesiser and voice processor in one.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ The TDMA based IS-136 uses puts three calls into the same 30kz channel space that AMPS uses to carry one call.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ When there were multiple positions that weren't covered by operators (like at night), an operator could use a plug from her switchboard in a jack of one on either side.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
In large towns served by a number of exchanges the junction
equipment is an important feature. In many cases from 60 to 80 per
cent. of the calls originated at an exchange are for subscribers
connected to other exchanges, and in these cases the junction plant
forms a considerable fraction of the whole equipment. Moreover each
call junctioned is dealt with by at least two operators.
.^ Interesting Switchboard with only two positions with cords, but a third position with jacks for subscribers on the far right (used by right set of cords).- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ When businesses began installing multiple phones within their buildings, an on-site switchboard was used to connect a particular phone to an outside line.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ In the beginning, you couldn't even call someone who was a subscriber in the competing system, since the lines didn't connect anywhere.- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
.^ In many areas, the wire-line carrier will be the local operating company.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Surplus Army Field Phones and Wire Device to Eliminate Induced AC Voltage on the Line Early Amplifier went Inside Handset or Phone Unusual Hand Held Circuit Loss Testing Tool .- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
During the
progress of these operations the A operator connects the
originating subscriber to the junction circuit named by the B
operator.
.^ Interesting Switchboard with only two positions with cords, but a third position with jacks for subscribers on the far right (used by right set of cords).- Telephone History... Antique Telephone & Collector's Items 11 January 2010 10:40 UTC www.sandman.com [Source type: General]
^ Yes, there is a control frequency but the mobile can only transmit on one frequency at a time.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Searching through its list of forward control channels, it picks one with the strongest signal, the nearest cell or sector usually providing that.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
Control
of the call is thus vested in the operator at the originating
exchange, at which point the connexion must be severed before a
clearing signal can appear at B.
Party Lines
.^ Demultiplexing those conversations is no more difficult than adding the right circuit board to a personal computer.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One desirable feature of a mobile telephone system is the ability to roam; that is, subscribers must be able to call and be called in cities other than their home areas.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ It's important to remember, though, that depending on the technology used, one carrier might provide more connections than a competitor does with the same amount of spectrum.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ [Clone comments] "You could make more clear that this is due to validation and fraud issues, not to the mechanics of setting up the call, since this is pretty much the same for originations and terminations."- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ There NEVER was a place I could not call from and reach home--clear as a bell.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
^ Apple s latest iPhone 3G will be more profitable than any other product in its line-up, which includes iPods, Macs, and iTunes.
.^ The FCC intends cellular service to be regulated by competition, with two competing system providers in each large city: a wire-line carrier and a radio common carrier.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ An SAT is a high pitched, inaudible tone that helps the system distinguish between callers on the same channel but in different cells.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
Although the bells are
constantly in circuit their high impedance prevents any appreciable
interference with the telephonic currents.
.^ Base stations use one frequency of that channel and mobiles use the other.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ It's important to remember, though, that depending on the technology used, one carrier might provide more connections than a competitor does with the same amount of spectrum.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ That's since the mobile unit and the base station both need circuitry to transmit on one frequency while receiving on another.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
In city
districts the modern practice is to restrict the number to four
stations per line, and to equip the exchanges and stations for
selective ringing.
.^ Like the one the businessman is now using.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ There are variations of TDMA. The only one that I am aware of in America is E-TDMA. It is or was operated in Mobile, Alabama by Bell South.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ The GSmart t600 also boasts a two-megapixel camera with macro capabilities, four-band GSM connectivity, WiFi, and Bluetooth 2.0.- The Windows Mobile Phones Showcase - Windows For Devices Articles - Windows for Devices 28 January 2010 1:30 UTC www.windowsfordevices.com [Source type: General]
.^ Because of the availability of the MJ system to subscribers requiring the roam feature, the MK system need not be arranged for roaming..- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ When a system is newly installed in an area (when large cells are serving only a few customers), frequency reuse is unnecessary.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ In the same way AMPS is also an operating system, using a different access technology, FDMA, or frequency division multiple access.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ In particular, cell phones or mobiles use the frequencies from 824.04 MHz to 848.97 and the base stations operate on 869.04 MHz to 893.97 MHz.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
Of the four bells connected to a circuit each responds to a
different frequency.
Missing image
Telephone-12.jpg
Trunk Line Working
.^ Let's say you're making a long distance call.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Countries covered The Mobal GSM World SIM works in all of the 170 countries in the dropdown list at the top of the page, as long as your handset is compatible.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
^ Countries covered The Mobal GSM World SIM works in all of the 170 countries in the dropdown list below, as long as your handset is compatible.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
.^ One desirable feature of a mobile telephone system is the ability to roam; that is, subscribers must be able to call and be called in cities other than their home areas.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Let's say you're making a long distance call.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ In the same way AMPS is also an operating system, using a different access technology, FDMA, or frequency division multiple access.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
At the Post Office a record operator replies and takes
particulars of the connexion, and these are entered upon a
ticket.
.^ These digital signals are repeated several times to make sure they get received.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ When the signal is received, the codes are removed from the desired signal, separating the users and returning the call to a rate of 9600 bps."- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
Meanwhile the ticket is conveyed to the
position where the lines to the town wanted are terminated.
.^ There NEVER was a place I could not call from and reach home--clear as a bell.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
^ A telegraph key tap broke the circuit momentarily, transmitting a short pulse to a distant sounder, interpreted by an operator as a dot.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Call capacity gets increased over normal TDMA. This trick had been limited before to very high density telephone trunks passing traffic between toll offices.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
i
Exchanges.
2+f From the Post Office Electrical Engineers' Journal.
FIG. 13. - Typical Cord Circuit, British Insulated Co.'s
System.
circuits to the trunk exchanges where the necessary connexions
are made between the trunk line and the junctions.
.^ The messages include the identities of called mobiles, local general control information, channel assignments for active mobiles and "filler" words to maintain synchronism.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Transmission, the process of transmitting, of conveying intelligence from one point to another, is a long settled, traditional way to express how signals are sent along.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ The slots themselves hold individual call information within the frame, that is, the multiplexed pieces of each conversation as well as signaling and control data.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
The large modern trunk exchanges are equipped with relays and
lamps for signalling purposes. " Calculographs " are employed for
stamping the time upon the tickets, and there is associated with
each trunk circuit a
device
which lights a lamp as soon as the scheduled limit of the period of
conversation is reached.
Missing image
Telephone-13.jpg
.^ Call capacity gets increased over normal TDMA. This trick had been limited before to very high density telephone trunks passing traffic between toll offices.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Registration lets the local system know that a phone is active, in a particular area, and that the mobile can now take incoming calls.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
This arrangement permits particulars of calls to be passed
over lines while conversations are in progress.
Automatic Systems
.^ Right now all digital cellular radio systems are second generation, prioritizing on voice traffic, circuit switching , and slow data transfer speeds.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ What was stripped out was the Roam and the Manual features, and the operator-selected-channel option.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One desirable feature of a mobile telephone system is the ability to roam; that is, subscribers must be able to call and be called in cities other than their home areas.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Voice traffic is digitized and portions of many calls are put into a single bit stream, one sample at a time.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Since calls are separated by time TDMA can put several calls on one channel.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ The TDMA based IS-136 uses puts three calls into the same 30kz channel space that AMPS uses to carry one call.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ A five digit code called the home system identification number (SID or sometimes SIDH) identifies the cellular carrier your phone is registered with.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Right now all digital cellular radio systems are second generation, prioritizing on voice traffic, circuit switching , and slow data transfer speeds.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One desirable feature of a mobile telephone system is the ability to roam; that is, subscribers must be able to call and be called in cities other than their home areas.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ In addition to channel assignment, other MTSO functions include maintaining a list of busy (that is, off-hook) mobile units and paging mobile units for which incoming calls are intended.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ I do make calls on my phone, but not as much as I use data service so call quality really isn’t that big of an issue as long as I’m able to hear the other side and they can hear me.
^ Once at the receiver the equipment identifies the call, separates its pieces from the spreading code and other calls, and returns the signal back to its original 9600 bit rate.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ And iDEN is, well, iDEN, a proprietary operating system built by Motorola (external link) that, among others, NEXTEL uses.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ The TDMA based IS-136 uses puts three calls into the same 30kz channel space that AMPS uses to carry one call.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ The mobile switch assigns which of those channels to use for a given call, but has no ability to assign other channels.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
The subscribers' lines in an exchange are arranged in groups of
moo, which are divided in turn into sub-groups of 100 each.
.^ All incoming and outgoing calls are then routed over this channel.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ A call gets going, in other words, on the control channel first and then drops out of the picture once the call gets assigned a voice channel.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ As the Cellular Development group puts it, "A CDMA call starts with a standard rate of 9600 bits per second (9.6 kilobits per second).- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Before we turn to another multiplexing scheme, CDMA, let's consider how a digital cellular phone determines how to choose a digital channel and not an analog one.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Right now all digital cellular radio systems are second generation, prioritizing on voice traffic, circuit switching , and slow data transfer speeds.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ At the same time, the number of customers in a large city can be increased from a maximum of about one thousand for a conventional system to several hundred thousand.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Not only in the number of countries it works in, but also the number of carriers it connects to in each country — in fact, you’ll get better coverage than many of the locals get, as they will be stuck using just one carrier.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
.^ A call gets set up on a control channel and another channel actually carries the conversation.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Punch out the number that you want to call.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Once everyone was in the store with their bag checked, I called our conductor Agent Kula back in Union Square and told him it was time for the first movement.- Cell Phone Symphony « Improv Everywhere 31 January 2010 13:24 UTC improveverywhere.com [Source type: General]
^ New gadgets can be complicated at the best of times, especially when you have to overcome the complexities of overseas dialing codes and unfamiliar telephone number formats.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
Wire Plant
In suburban and rural districts subscribers are usually served
by means of bare wires erected upon wooden or iron poles.
.^ You may drive fifty miles, use 8 different cells and never once realize that your call has been transferred.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
In large towns telephone distribution by means of open wires
is practically impossible, and the employment of cables either laid
in the ground or suspended from poles or other overhead supports is
necessary.
In the types of
cable that
were first used, the wires, usually with a
cotton insulation, were drawn
into
lead tubes, and the tubes filled
with
paraffin or other
similar compound, which kept the wires from the injurious effects
of any moisture which might penetrate the lead tube. This form of
cable has been superseded by a type with paper insulation. The
separate wires are surrounded only with a loose covering of
specially prepared paper, which furnishes abundant insulation. In
the manufacture of the cable the wires are first enclosed in the
paper, which is applied sometimes longitudinally and sometimes
spirally. The conductors are then twisted in pairs with definite
lays.
.^ Note that this list is not meant to be all-inclusive; many of the manufacturers represented here offer additional models covering a spectrum of features and specs.- The Windows Mobile Phones Showcase - Windows For Devices Articles - Windows for Devices 28 January 2010 1:30 UTC www.windowsfordevices.com [Source type: General]
^ Look up all of these terms in a good telecom dictionary and see what those writers state.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
The cable is then
placed in an
oven, and, after all
moisture has been driven off, it is passed through a lead press
whence it emerges protected by a continuous lead
pipe. The electrostatic capacity of a cable of
this type is low, and its dimensions are small, the external
diameter of a cable containing 1600 ten-lb conductors being only 24
in. The conductors used for subscribers' circuits are of
copper weighing from 10 to 20 lb
per mile. Junction circuits are usually made up of 20 or 40 lb
conductors.
.^ We use the terms 'cell' (the coverage area) and 'cell site' (the base station location) interchangeably, but they are not the same thing.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Start-up and small-city systems use a somewhat more conventional configuration with a single cell site at the center of each cell.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Make and receive calls from over 150 countries on the same number using standard direct dialing… .- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
Manholes are placed at
intervals in the line of ducts to facilitate the drawing in and
jointing of the cables, and surface boxes are placed in the
footways for distributing purposes. Various methods of making the
connexions between the large main cables and the subscribers are in
use.
.^ At the same time, the number of customers in a large city can be increased from a maximum of about one thousand for a conventional system to several hundred thousand.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
There, the large cables divide into a
number of small cables, which are carried along the footways in
pipes and are tapped at suitable points to serve subscribers.
.^ Increasing capacity means putting more calls into the same amount of spectrum which means calls may be blocked and voice quality will decrease.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
Aerial distribution from distributing poles is a
method frequently adopted. In this case the cables terminate upon
the poles, the connexions between the cable wires and the open
wires being made with rubber-covered leads.
.^ PM The long-awaited move to the use of mobile phones from different service...
Wire weighing
between 150 and 400 lb per mile is generally used. The
New York-
Chicago line, built in 1892, is of wire 165
millimetres in diameter (No. 8
Birmingham), weighing 435 lb per mile and
having a resistance of 2.05 ohms per mile. Speech has been
habitually transmitted for business purposes over a distance of
1542.3 m., viz., over the lines of the American Telegraph and
Telephone Company from
Omaha to
Boston. Conversation has been carried on over 2200 m. of No. 8
line.
As no practical process of telephone relaying has been devised,
it is extremely important that the character of the line should be
such as to favour the preservation of the strength and form of the
telephone current. In circuits possessing high resistance and
capacity and low inductance per mile, telephonic currents are
rapidly attenuated, and the higher the frequency the more rapid is
the attenuation. Moreover, as the velocity of
propagation is a
function of the frequency, there is distortion of the complex
waves.
.^ Cellular radio is like that, different ways to communicate but all having in common a distributed network of cell sites, the principle of frequency-reuse, handoffs, and so on.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ At slightly less than a half inch, the Q is 50 percent thinner than its top competitors, according to Mot.- The Windows Mobile Phones Showcase - Windows For Devices Articles - Windows for Devices 28 January 2010 1:30 UTC www.windowsfordevices.com [Source type: General]
^ The data rate is 48.6 Kbits/s, less than a 56K modem, with each slot transmitting 324 bits in 6.67 ms. How is this rate determined?- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
Many circuits have been " loaded " in the manner proposed by Pupin
during recent years, especially in underground cables, and it has
been found in practice that the transmission value of these when
loaded is approximately from three to four times their value
unloaded. Open aerial longdistance lines have also been loaded, but
not to the same extent. The introduction of inductance coils into
such circuits renders them more susceptible to trouble from
atmospheric electricity and
more sensitive to leakage variations.
.^ Other than the fact that it is used for identification and sales purposes, what else would one use the serial number from an i-phone?
^ Your mobile transmits that telephone number, along with a request for service signal, and all the information used to register a call to the cell site.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Its purpose is to expand a system's carrying capacity while still using the same numbers of frequencies.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
Attempts have been made to improve submarine cables in this
respect, and in 1906 a short cable " loaded " with Pupin coils was
laid across
Lake Constance.
.^ If you have two sectors facing the same way, even if they are some distance apart, you'll have the problems Mark just discussed.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
(H. R. K.)
Commercial Aspects. - The records of the telephone
industry in Great
Britain during the
thirty
years from 1877 to 1907 form an instructive chapter in the
industrial history of the country.
.^ Use of this site is governed by our Terms of Use and Privacy Policy Copyright ©1996-2010 Ziff Davis Enterprise Holdings Inc.- The Windows Mobile Phones Showcase - Windows For Devices Articles - Windows for Devices 28 January 2010 1:30 UTC www.windowsfordevices.com [Source type: General]
(
b) The obstructive use made by the
local authorities of their power to
veto underground wayleaves. (
c) The
remarkable success achieved by the National Telephone Company,
despite these obstacles, in developing an extensive organization
and a profitable business.
The chief events in chronological order are: 1876. Graham Bell's
telephone patent was granted for the
United
Kingdom.
1877. Edison's telephone patent was granted for the United
Kingdom.
1878. Professor D. E. Hughes invented the microphone, but did
not apply for
letters patent. The Telephone Company,
Limited, was formed to acquire Bell's patent.
.^ The first point is that cell phones and base stations transmit or communicate with each other on dedicated paired frequencies called channels.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
>> 1879. The Edison Telephone Company of
London was formed. Both the Bell and the Edison
Companies opened negotiations with the Post Office for the sale of
their patents to the government, but without success. The Edison
Company announced its intention to start telephone business in
London, and the Postmaster-General instituted proceedings against
the company for infringement of his
monopoly rights under the Telegraph Act
1869.
1880. The two companies amalgamated as the United Telephone
Company Ltd. Mr Justice Stephen decided (
Attorney-General v.
.^ One license went automatically to the local telephone companies, in telecom parlance, the local exchange carriers or LECs.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ The local telephone companies were called the wireline carriers.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Time division systems are now being regarded as legacy technologies, older methods that must be accommodated in the future, but ones which are not the future itself.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
1881. The company's appeal
against the decision was withdrawn, the Postmaster-General agreeing
to grant licences for restricted areas of about 5 m. in London and
about 2 m. in the provinces. The licences merely condoned the
infringement of the Telegraph Act 1869, and did not confer powers
to erect poles and wires on, or to place wires under, any
highway or private property.
.^ In time division multiple access we separate calls by time, one after another.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ We'll see with IS-136 that three calls are placed on a single radio channel, one after another.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ There are no other hidden fees or taxes or surcharges for each call or each day, just a simple flat rate of 10 cent per minute.- Cellular Phone Directory of Nebraska 11 September 2009 20:57 UTC nebraska.uscity.net [Source type: General]
^ You only pay 10 cent per minute for every call, local, long distance and roaming.- Cellular Phone Directory of Nebraska 11 September 2009 20:57 UTC nebraska.uscity.net [Source type: General]
of
the
gross revenues.
.^ To prevent any possible cross-subsidization or favoritism, the Bell operating companies must offer their cellular service through separate subsidiaries.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ At the same time, the number of customers in a large city can be increased from a maximum of about one thousand for a conventional system to several hundred thousand.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One license went automatically to the local telephone companies, in telecom parlance, the local exchange carriers or LECs.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ It's so you can talk and listen at the same time, just like on a regular telephone.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
1882. The Postmaster-General (Mr Fawcett) declared that
he would issue no more licences unless the licensees agreed to sell
telephones to the Post Office. As a result only eight companies out
of over seventy that had applied obtained or accepted licences.
1883. The Post Office proposed to engage in active competition
with the telephone companies, but the Treasury at that time opposed
this policy on the ground that the state should at most be ready to
supplement and not to supersede private enterprise.
1884. The licences within restricted areas having proved
unsuitable for the growing business, public opinion appealed to the
Post Office to issue new licences applicable to the whole country.
.^ Call capacity gets increased over normal TDMA. This trick had been limited before to very high density telephone trunks passing traffic between toll offices.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ There are no other hidden fees or taxes or surcharges for each call or each day, just a simple flat rate of 10 cent per minute.- Cellular Phone Directory of Nebraska 11 September 2009 20:57 UTC nebraska.uscity.net [Source type: General]
^ You only pay 10 cent per minute for every call, local, long distance and roaming.- Cellular Phone Directory of Nebraska 11 September 2009 20:57 UTC nebraska.uscity.net [Source type: General]
was continued.
.^ My phone worked great no matter where I called from…the plane right after landing, my hotel rooms, or anywhere in either city.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
.^ Nokia Siemens Networks sign MOU with Tamil Nadu government to set up new plant .
^ The only costs associated with the Mobal® World Phone are the purchase price, your delivery option and then the calls you make when traveling.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
^ Access to work (BES) and personal (BIS) email Mobile Email Blackberry Data is Required With The Purchase of This Device Check if AT&T Coverage is right for you Price w/New 2 Year Contract.- Cell Phones from wireless carriers AT&T, BlackBerry, Sprint, T-Mobile, Verizon Wireless 28 January 2010 1:30 UTC www.letstalk.com [Source type: General]
The United Telephone Company
asked parliament for rights of way in streets but was refused, and
its only right to place overhead wires was obtained by private
wayleaves.
1885. The United Telephone Company again applied unsuccessfully
for right to lay wires underground.
1888. The application of the company for permission to lay wires
in streets was again refused.
.^ Even though Ethiopia was listed as a country with coverage, I just could not believe that it would actually work there.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
^ More recent systems (the MJ system at 150 KHz and the MK system at 450 KHz) [ Improved Mobile Telephone Service or IMTS, ed.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
The various companies therefore amalgamated as the
National Telephone Company.
1890. The government had the option to buy out the: companies
under the licences of 1884, but did not exercise it. The Bell
telephone patents expired. The National Telephone Company applied
to the London County Council for permission to lay wires
underground and continued efforts till 1899 to obtain this power,
but without success.
.^ In the international cell phone industry many new companies and services appear and disappear, leaving their customers searching for a replacement.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
.^ But at the same time, Smart phone speed will be… read more… .
^ CDMA features soft handoffs, where two or more cell sites may be handling the call at the same time.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ More recent systems (the MJ system at 150 KHz and the MK system at 450 KHz) [ Improved Mobile Telephone Service or IMTS, ed.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
The
government again changed its policy.
.^ How does a Real Estate company sell its office without causing confusion?
^ In many areas, the wire-line carrier will be the local operating company.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One license went automatically to the local telephone companies, in telecom parlance, the local exchange carriers or LECs.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
It also expressed
willingness that the companies should have rights of way in the
streets.
1893. The National Telephone Company again applied to parliament
for power to lay wires underground, but was refused.
.^ One license went automatically to the local telephone companies, in telecom parlance, the local exchange carriers or LECs.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ The local telephone companies were called the wireline carriers.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ In many areas, the wire-line carrier will be the local operating company.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
1895. A select committee of the House of Commons (with Mr Arnold
Morley, Postmaster-General, as
chairman) was appointed " to consider and report whether the
provision now made for the telephone service in local areas is
adequate, and whether it is expedient to supplement or improve this
provision either by the granting of licences to local authorities
or otherwise." The committee was not unanimous and made no report,
but merely submitted to the House the evidence it had taken.
.^ In many areas, the wire-line carrier will be the local operating company.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
1897. The government had an option to purchase the plant of the
company under the licences of 1884, but did not exercise it.
.^ The efficient use of frequencies that results from the cellular approach permits Advanced Mobile Phone Service customers to enjoy a level of service almost unknown with present mobile telephone service.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Even though Ethiopia was listed as a country with coverage, I just could not believe that it would actually work there.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
^ Moving from one service area to another causes registration to begin again.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ The FCC intends cellular service to be regulated by competition, with two competing system providers in each large city: a wire-line carrier and a radio common carrier.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
1898. The policy of the government was again changed; Mr R. W.
Hanbury, Financial Secretary to the Treasury and representative in
the House of Commons of the PostmasterGeneral, advocated the
granting of licences to local authorities. A select committee was
appointed with Mr Hanbury as chairman to consider " whether the
telephone service is calculated to become of such general benefit
as to justify its being undertaken by municipal and other local
authorities, and if so under what conditions." The committee
reported (9th August) that the telephone service was not likely to
become of general benefit " so long as the present practical
monopoly in the hands of a private company shall continue."
.^ My contract with Verizon ends in a few months and I’ve been researching other companies as I feel I’m paying too much for Verizon’s service.
^ In the international cell phone industry many new companies and services appear and disappear, leaving their customers searching for a replacement.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
.^ This means having upgrades done in order to make it the best ride you can afford.
^ In a continuing effort to provide the best wireless service for local residents in Orange County, Verizon Wireless has expanded its network with a new cell site in Cornwall.
.^ System Operation: Unlike the MJ and MK systems, Advanced Mobile hone Service dedicates a special subset of the 333 allocated channels solely to signaling and control.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Also, because of the stored-program control capability of MTSOs equipped with the lAESS system, Custom Calling Services and man other features can be offered, some unique to mobile service.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ More recent systems (the MJ system at 150 KHz and the MK system at 450 KHz) [ Improved Mobile Telephone Service or IMTS, ed.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ One license went automatically to the local telephone companies, in telecom parlance, the local exchange carriers or LECs.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ The local telephone companies were called the wireline carriers.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One license went automatically to the local telephone companies, in telecom parlance, the local exchange carriers or LECs.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Originally, all mobile telephone systems operated manually, much as most private radio systems do today.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ The local telephone companies were called the wireline carriers.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One license went automatically to the local telephone companies, in telecom parlance, the local exchange carriers or LECs.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ In many areas, the wire-line carrier will be the local operating company.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
In February the Postmaster-General applied for an
injunction to restrain
the company from opening any street or public road within the
county of London without the consent of the Postmaster - General
and the London County Council, which injunction was granted in
July.
1901. The government policy of 1899 was abandoned in London, the
Post Office making an agreement with the company in regard to the
London business. The company consented to free intercommunication
between its subscribers and those of the Post Office, and undertook
to charge rates identical with those charged by the Post Office.
The Postmaster-General on the other hand agreed to provide
underground wires for the company on a rental, and agreed to buy in
1911 the company's plant in London at the cost of construction less
allowance for
repairs and depreciation.
1904. The government had option to purchase the company's
provincial plant under the licence of 1884. Negotiations took
place, but no agreement was reached.
1905. The government contracted to buy the company's plant in
1911, thus in effect annulling the act of 1899 which had failed to
accomplish its object of establishing all-round competition.
.^ The Bell System originally planned for 1000 channels but was given only 666 by the FCC. When cellular proved popular the FCC was again approached for more channels but granted only an extra 166.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ One license went automatically to the local telephone companies, in telecom parlance, the local exchange carriers or LECs.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
Hull and Portsmouth were the only municipal telephone
systems working in 1907.
.^ The local telephone companies were called the wireline carriers.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One license went automatically to the local telephone companies, in telecom parlance, the local exchange carriers or LECs.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Because of these effects, radio channels can be used reliably to communicate at distances of only about 20 miles, and the same channel (frequency) cannot be reused for another talking path less than 75 miles away except by careful planning and design.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One desirable feature of a mobile telephone system is the ability to roam; that is, subscribers must be able to call and be called in cities other than their home areas.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ The Mobal World Phone offer is only available to North American residents.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
.^ A built-in SD/MMC expansion slot enables file storage on removable Flash media.- The Windows Mobile Phones Showcase - Windows For Devices Articles - Windows for Devices 28 January 2010 1:30 UTC www.windowsfordevices.com [Source type: General]
Within
six years the services had been extended to 400 towns with about
55,000 subscribers. Large as this progress was it would have been
much greater if the Telephone Company had been granted adequate
powers to put wires underground and thus instal a complete metallic
circuit in place of the single wire, earthreturn, circuit which it
was constrained to employ. Subsequently the progress was still
greater.
.^ God, Country, and Notre Dame is more than an inscription above an entrance to the Sacred Heart Church on the campus of Notre Dame and more than the title of Father Ted Hesburgh s autobiography.
.^ Even though Ethiopia was listed as a country with coverage, I just could not believe that it would actually work there.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
^ Mobal’s GSM World Phone works in over 150 countries with no minimums, fees or service charges.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
^ Unlike many other phones, the Mobal GSM World Phone works well in over 150 countries, and you never need to change the SIM card.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
.^ At the same time, the number of customers in a large city can be increased from a maximum of about one thousand for a conventional system to several hundred thousand.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
The only European
country which can be compared with the United Kingdom in telephone
development is Germany. With a population of 58 millions there are
10.2 telephones per
loon of the
population in that country compared with 10 15 in Great Britain and
Ireland.
.^ It doesn't get much more authoritative than the guys who developed the stuff!"- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
of the
population were telephone subscribers.
Tariffs
.^ This pair of Windows Mobile PDA/phones come with a range of services that target the needs of small and medium-sized businesses (SMBs).- The Windows Mobile Phones Showcase - Windows For Devices Articles - Windows for Devices 28 January 2010 1:30 UTC www.windowsfordevices.com [Source type: General]
^ Two of the VoIP phone services that are used frequently by businesses are Jajah and Lingo.
^ May require a one or two year service term agreement with featured wireless carrier.- Cell Phones from wireless carriers AT&T, BlackBerry, Sprint, T-Mobile, Verizon Wireless 28 January 2010 1:30 UTC www.letstalk.com [Source type: General]
The
original method of charging adopted in Great Britain took the
telephone instrument as the unit, charging a fixed annual rental
independent of the amount of use to which the instrument was put.
.^ HTC's Touch Dual uses the TouchFLO user interface that made its debut with the HTC Touch , but also includes a slide-out QWERTY keyboard.- The Windows Mobile Phones Showcase - Windows For Devices Articles - Windows for Devices 28 January 2010 1:30 UTC www.windowsfordevices.com [Source type: General]
^ The HTC-manufactured HT1100 uses the TouchFLO user interface that made its debut with the HTC Touch , but also includes a slide-out QWERTY keyboard.- The Windows Mobile Phones Showcase - Windows For Devices Articles - Windows for Devices 28 January 2010 1:30 UTC www.windowsfordevices.com [Source type: General]
^ Gigabyte Communications offers a smartphone wrapping Windows Mobile 6.5 in a custom "SmartZone" user interface built using Adobe's Flash technology.- The Windows Mobile Phones Showcase - Windows For Devices Articles - Windows for Devices 28 January 2010 1:30 UTC www.windowsfordevices.com [Source type: General]
.^ Membership has actually grown to more than one hundred th...
^ Later, as the service grows, a dense system will have many small cells and many customers), a given channel in a large city could be serving customers in twenty or more nonadjacent cells simultaneously.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Apple s latest iPhone 3G will be more profitable than any other product in its line-up, which includes iPods, Macs, and iTunes.
.^ In any given area, both the size of the cells and the distance between cells using the same group of channels determine the efficiency with which frequencies can be reused.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Most cells have been split into sectors or individual areas to make them more efficient and to let them to carry more calls.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
But the tendency is
towards a system of charging a moderate sum to cover the
rent of the instrument and an
additional
fee per message. For
instance, in the county of London, the telephone
tariff is £5 per annum plus id. per call within
the county and 2d. per call outside the county. Subscribers outside
the county of London pay only £4 in annual subscription and id. per
call to sub - scribers on the same exchange and 2d. per call to
subscribers on other exchanges. In each case the minimum annual
amount for message fees is £1,. los. The alternative is given of an
unlimited service (" flat rate ") at £17 per annum. In the
provinces the unlimited service
costs only £7, tos. for subscribers within half a
mile of the exchange, £1, 5s. being charged for every additional
quarter of a mile or fraction thereof. The
toll or message rates are £3, with id. per call,
with a minimum of £1, Ios.
.^ A frequency might be 1.25 or even 5 MHz wide, 10 times or more the width a conventional call might use.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Inmates are being overcharged when they phone home - prisoners are charged seven times the rate from a standard call box for a half-hour call to loved ones.
^ Qualcomm's CDMA system uses some very advanced speech compression techniques, utilizing a variable rate vocoder, a speech synthesiser and voice processor in one.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
The tariff for unlimited use has to be
made very high to cover the cost of the additional burdens thrown
upon the service, and it only works economically to the individual
subscriber who has an exceptionally large number of calls
originating from his instrument. The message-rate system equalizes
the charges according to the service rendered.
.^ Maintenance of this ratio ensures that a majority of users will rate the service quality good or better.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Punch out the number that you want to call.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ A frequency might be 1.25 or even 5 MHz wide, 10 times or more the width a conventional call might use.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Instead of concentrating a message in the smallest spectrum possible, say in a radio frequency 10 kHz wide, CDMA spreads that signal out, making it wider.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ (Time division duplexing, as used in cordless telephone schemes: DECT and Personal Handy Phone systems might have a place but this still isn't clear.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Qualcomm's CDMA system uses some very advanced speech compression techniques, utilizing a variable rate vocoder, a speech synthesiser and voice processor in one.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One desirable feature of a mobile telephone system is the ability to roam; that is, subscribers must be able to call and be called in cities other than their home areas.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ The FCC intends cellular service to be regulated by competition, with two competing system providers in each large city: a wire-line carrier and a radio common carrier.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
per call to subscribers within the county and 2d. per call to those
outside it, with a minimum of £3.
.^ Your mobile transmits that telephone number, along with a request for service signal, and all the information used to register a call to the cell site.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
per message.
The trunk line service is charged for on rates which vary from
3d. (for 25 m.) up to is. (for 100 m.) for a three minutes'
conversa - tion between 6 a.m. and 8 p.m. For every 40 m. above Too
m. an additional 6d. per conversation is charged.
.^ Inmates are being overcharged when they phone home - prisoners are charged seven times the rate from a standard call box for a half-hour call to loved ones.
and 7 a.m. A call between London and
Liverpool, which ordinarily
costs 2s., can be made for is. between those hours. The growth of
traffic on this basis has been considerable, and the arrangement
has proved of advantage to the public, as it provide, cheap
facilities at times which are convenient for social
conversation.
.^ One desirable feature of a mobile telephone system is the ability to roam; that is, subscribers must be able to call and be called in cities other than their home areas.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One license went automatically to the local telephone companies, in telecom parlance, the local exchange carriers or LECs.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
Subscribers to exchanges may also make
arrangements to have all telegrams (except Press telegrams) ad -
dressed to them delivered by telephone instead of messenger.
Telephone subscribers may also obtain the services of an express
messenger by telephoning to the nearest post office connected with
the exchange.
|
15,000 6% 1st preference shares of £10 each.
|
. £150,000
|
|
15,000 6% 2nd preference shares of Do each
|
. 150,000
|
|
250,000 5% 3rd preference shares of £5 each .
|
. 1,250,000
|
|
6% preferred stock. ... .
|
. 2,225,000
|
|
Deferred stock. .. .. .
|
. 3,366,425
|
|
71,715 new shares of £5 each.. .
|
. 358,575
|
|
£ 7,500,000
|
|
31% debenture stock .
|
. 2,000,000
|
|
4% debenture stock .
|
. 1,716,593
|
|
fI I,216, 593
|
National Telephone Company. - The issued share and
debenture capital of the company on the 31st of December 1907 was:
- The company has a reserve fund of £2,467,707, the major part of
which is invested in the business. The gross income for the year
1907 amounted to £2,702,228, of which £257,920 was paid to the Post
Office in respect of royalties. The working expenses amounted to
£1,530,093 or 62.6 per cent. of the
net income, leaving a profit for the year of
£914,216.
.^ New gadgets can be complicated at the best of times, especially when you have to overcome the complexities of overseas dialing codes and unfamiliar telephone number formats.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
The business subsequently proved
profitable, good dividends were paid, and the securities for the
most part commanded a
premium in the market.
.^ AT&T, which made $3.46 billion in profits during the first quarter, hopes to increase prices for wireline phone services in Tennessee starting July 26.
^ In the international cell phone industry many new companies and services appear and disappear, leaving their customers searching for a replacement.- International Cell Phone and World Phones for Travel 31 January 2010 13:24 UTC www.mobal.com [Source type: General]
Agreement of 1905
.^ Right now all digital cellular radio systems are second generation, prioritizing on voice traffic, circuit switching , and slow data transfer speeds.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ The first law prohibits all drivers from using a handheld wireless telephone while operating a motor vehicle.
^ Your mobile transmits that telephone number, along with a request for service signal, and all the information used to register a call to the cell site.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
The price is
to be fixed by the
Railway
and Canal Commissioners as arbitrators on the basis of the " then
value," exclusive of any allowance for past or future profits or
any compensation for compulsory sale or other consideration. In
those cases in which the company's licence has been extended beyond
1911 (Glasgow to 1913, Swansea to 1926, Brighton to 1926 and
Portsmouth to 1926) the Postmaster-General will buy the unexpired
licence with allowance for
goodwill.
.^ In many areas, the wire-line carrier will be the local operating company.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ Cell size is based on the traffic density expected in the area and can range from 1 to 10 miles in radius.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ One license went automatically to the local telephone companies, in telecom parlance, the local exchange carriers or LECs.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
Free intercommunication was established
by the agreement between the subscribers of the company and those
of the Post Office, and a scale of charges was adopted or arranged
to be agreed as binding on both the Post Office and the company.
.^ Before we get to them, let's stop here and review, because it is hard to think of the big picture, the overall subject of cellular radio, when we get involved in details.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ No setting up on one radio frequency channel and then moving off to another.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
The company had had to pay for all the experiments and mistakes
which are inherent in the launching and development of any new
industry. It had paid the Post Office in royalties already
£1,848,000, and the Post Office under the agreement would step into
the business in 1911 by merely paying for the plant employed. The
Association of Municipal Corporations and the London County
Council, on the other hand, considered the terms of purchase to be
too favourable to the company. The London County Council, according
to the statement of its
comptroller, was disturbed by the hope
expressed by the manager of the company, that the holders of the
company's ordinary shares would obtain the par value of their
shares in 1911. Inasmuch as the debenture
stocks and preference shares would have to be
redeemed in 1911 at premiums ranging from 3 to 5 per cent., the
state would have to pay the company £253,000 in excess of the total
of the outstanding securities in order to enable the ordinary
shares to receive par, and in the council's view this payment would
diminish the p robability of the Post Office being able to afford a
substantial reduction in the telephone charges.
Post Office Telephones
The number of trunk wire centres open on the 31st of March 1907
was 533, and the total number of trunk circuits was 2043,
containing about 73,000 m. of double wire.
.^ The FCC intends cellular service to be regulated by competition, with two competing system providers in each large city: a wire-line carrier and a radio common carrier.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ During the development phase it was realized that deployment of CDMA meant turning off channels in the analog system.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
per conversation.
.^ One desirable feature of a mobile telephone system is the ability to roam; that is, subscribers must be able to call and be called in cities other than their home areas.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ By the seventies, it included a total of thirty-three 2-way channels below 500 megahertz MHz), as shown in Table 11-2.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
.^ Originally, all mobile telephone systems operated manually, much as most private radio systems do today.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
on the total expenditure of £7,252,000 was
£432,726.
.^ One desirable feature of a mobile telephone system is the ability to roam; that is, subscribers must be able to call and be called in cities other than their home areas.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
There were 425 post office
call-offices in the London area. The length of underground pipes
which had been laid in the metropolitan area for telephone purposes
was 2030 m. Cables containing 317,789 m. of wire had been laid,
including 69,066 m. rented by the National Telephone Company. The
average cost of constructing an exchange circuit in the
metropolitan area (including the
installation of telephone instruments and
of exchange apparatus, but excluding the provision of spare plant)
has been £33. Taking into account the whole system (including spare
plant of all kinds), the capital expenditure per station (i.e. per
telephone connected with an exchange) stands at less than £50.
International Telephone Lines
The Anglo-French telephone service, which was opened between
London and
Paris in April 1891,
was extended to the principal towns in England and France on the
11th of April 1904. The service has since been extended to certain
other English provincial towns; and the Anglo-Belgian telephone
service has similarly been extended.
.^ Right now all digital cellular radio systems are second generation, prioritizing on voice traffic, circuit switching , and slow data transfer speeds.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ It's important to remember, though, that depending on the technology used, one carrier might provide more connections than a competitor does with the same amount of spectrum.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
^ TDMA's chief benefit to carriers or cellular operators comes from increasing call capacity -- a channel can carry three conversations instead of just one.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
Experiments have been made in
telephonic communication between London and
Rome by way of Paris.
.^ Airphone, Nextel, SMR, and public safety services use the bandwidth between the two cellular blocks.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
REFERENCES
.^ Here's some great reading on the transition from mobile telephone service to cellular.- Cellular Telephone Basics 16 September 2009 22:41 UTC www.privateline.com [Source type: FILTERED WITH BAYES]
(E. GA.)
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