The Atari 2600 went through many makeovers and revisions in its 14 year history. The system also contained a large number of controllers and third-party peripherals.
The Atari had a large number of input devices (such as joysticks, paddles, keyboards, etc...) as well as third-party components.
The console came packaged with two standard joysticks and a set of paddles. Joysticks, featuring a single button and 4-directional stick, were used by most Atari game and was the predominate input device. Also, the Atari joysticks could be used in MSX and several Japanese computers. It is possible to use the joysticks in Sega systems like the Sega Master System or Sega Genesis in games that only require one button.
The other main controller, the paddle, was used for games based on one-dimensional movement. These included Pong, Breakout, and Circus Atari, to name a few. The "driving controller" appeared similar in design to the paddle, but there was only one per DE-9 port rather than two paddles per port. The key difference in function between the paddle and driving controller was that the paddle's wheel had a finite amount it would turn before hitting a stop, while the driving controller's wheel could rotate continuously. This was essential for overhead-view driving games, for which you would have to turn the wheel a total of 360 degrees in one direction every lap.
There were two different designs for the six switch models. Both designs incorporated a switch board and a motherboard which were connected by a 12-pin ribbon cable.
For their first year of production (1977), Atari manufactured the CX2600 with heavy aluminum radio frequency shielding as well as 1/2 inch thick plastic bottom half. These units are easily differentiated from other years of production by their thick molding on the sides of the case, the curved molding on the front of the unit, as well as their heavier weight, giving them the nickname "Heavy Sixer".
These models were introduced in 1978 and stayed in production for about two years. The thick molding on the sides and curved molding on the front gave way to thinner and more sharply angled molding reducing the weight of the system. The front right and left molding are angular and overlap the woodgrain. The thick RF shielding remained until the four switch models came out. Atari also included a channel select switch on the bottom right hand side of these systems for the first time.
These models also had two different designs. For the most part, the only difference between the four switch models and the "Light Sixer" is that there are only four switches and retain much of the same moldings. Instead of having two separate boards connected through a ribbon cable, the CX2600-A had one motherboard.
These models were introduced in 1980. They are similar to the CX2600 "Light Sixer" except where the two difficulty switches were removed from the front of the console to the back. This left four front switches.
These models were introduced in 1982 and were the first to use
"2600" in its name. Besides containing a different logo than
earlier models, this model does not have woodgrain on the front and
are primarily black, resulting in the nickname of "Darth
In 1986, a new version of the 2600 was released (although it was
planned for release two years earlier). The new redesigned version
of the 2600, unofficially referred to as the 2600 Jr., featured a
smaller cost-reduced form factor with a modernized Atari 7800-like
appearance. The redesigned 2600 was advertised as a budget gaming
system (under $50) that had the ability to run a large collection
of classic games.
The Atari 2600 VCS Domestic Field Service Manual describes the differences as follows:
In addition to the component changes, the physical location of several parts has also been changed. Instead of having the right and left difficulty switches placed on top of the game, they are located at the rear of the console next to the game controller plugs. The channel selector switch is also located at the rear of the console. The game cartridge socket is no longer angled, but is mounted vertically on the board.
2600A model differences - revisions 14 and 15
Revisions 14 and 15 contain the model differences described above, and in addition have new components on the TIA lines, LM1 and Sync. There are two IN914 diodes to prevent feedback on the lines and two additional pull-up resistors to insure the signal is at +5v. To compensate for any signal loss, R215 and 217 have been changed to 47K (R215) and 24K (R217).
2600A model differences - revisions 16 and
The Atari 2600 used different color palettes depending on the television signal format used. With the NTSC format, a 128-color palette was available, while in PAL, only 104 colors were available. Additionally, the SECAM palette consisted of only 8 colors.
The Television Interface Adapter(TIA) chip CO1044(D), CPU chip CO10745, and combination Ram+I/O chip CO10750 are the same used throughout the 2600's production.