Magnavox concluded their line of dedicated video game consoles with the Odyssey 4000. The Odyssey 4000 (Model 7511) dedicated console was released in 1977. Based around the AY-3-8600 single-chip design, the 4000 features a total of seven games (Tennis, Hockey, Volleyball, Basketball, Knockout, Tank, and Helicopter) that with variations can be expanded to twenty-four different gaming experiences. The unit allows up to four players and includes a Practice mode for solo-play against the computer. As with the 3000, the 4000 offers a skill switch for novice, semi-pro, and professional skill levels. Additional features include automatic serve, variable ball speeds, and a pause button. Unlike the Odyssey 3000, the 4000 featured detachable joysticks. The AY-3-8615 chip enabled the Odyssey 4000 to display color instead of black and white graphics. The 4000 is powered by an included AC adapter.
Source: Wikipedia, "[en.wikipedia.org/wiki/Magnavox_Odyssey_series%23Odyssey_4000 Magnavox Odyssey series]", available under the CC-BY-SA License.