|Closed||October 1, 1997|
|Owned by||Spectacor (1976-1983)
Rainbow Media (1983-1997)
|Broadcast area||Philadelphia metropolitan area|
|Replaced by||Comcast SportsNet Philadelphia|
|Sister channel(s)||SportsChannel Philadelphia|
PRISM (Philadelphia Regional In-Home Sports and Movies) was a 24-hour premium cable television channel intended for cable customers in the Philadelphia, Pennsylvania metropolitan area. Launched in September 1976, PRISM broadcast both through cable systems and, from 1983 to 1985, through a scrambled over-the-air signal on WWSG-TV, channel 57. The relationship ended when WWSG was sold and converted into conventional independent WGBS-TV (now WPSG).
PRISM was launched in 1976 by Spectacor, the owner of the Philadelphia Flyers. Its administrative offices were in Bala Cynwyd, Pennsylvania while its studios, production facilities, and master control room were all situated in The Spectrum (event level) at Broad Street and Pattison Avenue in Philadelphia. What differentiated PRISM from other services – some of which included ON-TV, SelecTV, and Z Channel – is that it broadcast exclusive and extensive sports coverage, which included Flyers, Philadelphia Phillies, and Philadelphia 76ers games, Big 5 basketball, and live World Wrestling Federation events held at The Spectrum. Its sports coverage extended to sports-based original programming, such as Broad & Pattison (the South Philadelphia intersection of the city's sports complex) and The Great Sports Debate. PRISM also broadcast a selection of movies and non-sports programming, such as PRISM Kids and Live At Rafters.
In 1983, PRISM was sold to Rainbow Media, along with PRISM New England (now CSN New England) which was launched two years earlier. Rainbow later launched a companion basic cable channel; SportsChannel Philadelphia, an affiliate of Rainbow's SportsChannel America network, signed on in 1990. The channels, however, had separate graphic and music packages and announcing teams until 1995, when all sports presentation was made uniform.
The 1980s three-stripe logo PRISM had been using since 1976 was retired in mid-1993 in favor of a modern logo and identity that came with a revamp that attempted to spice up PRISM's non-sports programs. PRISM began using the Univers typeface in its entire identity package. It was used for everything from the logo to text during sports coverage.
Rainbow Media launched websites for all of its television channels in 1996, including PRISM. 
In 1996, Comcast acquired a majority stake in Spectacor (PRISM's former owner) to form Comcast Spectacor, which immediately bought the 76ers. It then announced plans for a new all-sports network centered around those teams, effectively driving a stake through the heart of PRISM and SportsChannel Philadelphia. After a year of uncertainty that included plans for PRISM and SportsChannel to affiliate with Fox Sports Net, Comcast, Liberty Media, and Rainbow came to an agreement. PRISM and SportsChannel closed for good on October 1, 1997, but with designated successors: PRISM would give way to Liberty's Starz! movie channel, and the new Comcast SportsNet replaced SportsChannel Philadelphia on the area's cable systems.
PRISM's legacy is noteworthy because Comcast SportsNet Philadelphia continues to distribute its signal to Cable TV providers via PRISM's terrestrial infrastructure using only microwave and fiber optics. Comcast SportsNet does not uplink to any satellite. A controversial FCC guideline (known as the "terrestrial exception") implemented to encourage investment in local programming states that a television channel does not have to make its shows available to satellite companies if it does not use satellites to transmit its programs. This guideline has allowed Comcast to block DirecTV and Dish Network from carrying Comcast SportsNet Philadelphia, but it has offered the sports network to Verizon's FiOS service. Consequently, market penetration by Direct broadcast satellite providers in the Philadelphia area is much lower than in other cities.