The Intellivision (short for Intelligent Television) was released by Mattel to compete with Atari only a year after the release of the 2600. The system was released in 1978 to a small market, before being available nationwide in 1980. The system launched with Las Vegas Poker & Blackjack as a pack-in, and 4 other titles available.
The Intellivision was known for its major graphic and gameplay enhancements over the 2600, and Mattel made deals with many store chains to sell re-branded units. These stores included Radio Shack, and Sears.
Originally all Intellivision games were developed by a small 5 man team in house; after two years on the market, the team had grown to over 100 members and third parties such as Activision and Imagic began making games for the console as well.
The controllers for the Intellivision were designed with a numeric keypad laid out like a phone, and a direction disc that can detect 16 directions of movement. The controller also features 4 buttons on the side, and a slot where overlays can be inserted over the keypads to explain which buttons do what. The controllers, while uncomfortable, were influential in the design of controllers for many consoles released in 82-83, including the Colecovision.
During the first couple years, Mattel promised many hardware expansions and enhancements for the Intellivision, but after a long delayed keyboard attachment, Mattel dropped many of these and instead launched the Entertainment Computer System (ECS) add-on, which allowed the Intellivision to be used as a computer. The system contained a keyboard, addition memory and a cassette drive for saving programs. The ECS was released just as popularity for the console was dropping and it received no success.
Another add-on was the Intellivoice, which allowed some games to produce voice. The amount of voice able to be stored on the cartridges was limited, but some developers integrated the speech into the gameplay mechanics of their games.
In 1983, Mattel released the Intellivision 2. The system was a smaller model, and featured detachable controllers. It was also able to play Atari 2600 games. The system also featured some changes to the lockout code that should have prevented third party titles from being playable, but the third parties quickly found a workaround and most games are still playable on the Intellivision 2.
In 1983, with the release of 5 new consoles and the bad state of the video games industry, the Intellivision sales started dropping drastically. In early 1984, Mattel had shut down the Intellivision division entirely and the rest of the stock was sold off to former Mattel Marketing executive, Terry Valeski. He continued to sell the stock, and when they ran out of units, he built a new console called the INTV3, or Super Pro System, which was basically the same as the Intellivision 2 but with a slight cosmetic redesign. The system was discontinued in 1991.
Rights then went to Keith Robinson, an early Intellivision programmer, who repackaged the games and sold PC,Xbox,PS2, and Gamecube Compilations.