The Entertainment Computer System (ECS) was an add-on peripheral for the Intellivision. It was Mattel Electronics' second attempt at creating a peripheral to upgrade the Intellivision into a home computer, and was rushed into production to appease the Federal Trade Commission after they began fining Mattel for false advertising following consumer complaints about the repeated delays in releasing the originally planned Intellivision Keyboard Component add-on.[1] The ECS includes the Computer Module, Music Synthesizer, and additional hand controllers; each sold separately. Any Intellivision Master Component is compatible and a requirement to use the system. A second requirement is a cartridge plugged into the ECS, although any ECS or Intellivision cartridge will do; pressing anything on the Intellivision hand controllers will then bring up the three-option menu of BASIC, CARTRIDGE or MUSIC.[2]