The Atari 5200 SuperSystem, or simply the Atari 5200, is a video game console that was introduced in 1982 by Atari Inc. as a replacement for the popular Atari 2600. The 5200 was created to compete with the Intellivision, but wound up more directly competing with the ColecoVision shortly after its release.
The 5200 was based on Atari Inc.'s existing 400/800 computers and the internal hardware was almost identical, although software was not directly compatible between the two systems. A number of design flaws had a serious impact on usability, and the system is generally considered to have performed poorly on the market.
Source: Wikipedia, "Atari_5200", available under the CC-BY-SA License.