DECO Cassette System

The DECO Cassette System is an arcade system that was introduced by Data East in October 1980. It was the first standardised arcade system that allowed arcade owners to change games. Developed in 1979, it was released in Japan in 1980 and then North America in 1981.

The arcade owner would buy a base cabinet, while the games were stored on standard audio cassette tapes. The arcade owner would insert the cassette and a key module into the cabinet. When the machine was powered on, the program from the tape would be copied into the cabinet's RAM chips; this process took about two to three minutes. Afterwards, the game could be played freely until the machine was powered off.

The machine contained three processors. The main central processing unit (CPU) was the DECO 222, a modified version of the MOS 6502 running at 750 kHz. This was largely identical to the normal 6502 but included hardware encryption that worked with the cassettes. A second unmodified 6502 running at 500 kHz was used to program the sound, which was produced by two General Instrument AY-3-8910 sound chips running at 1.5 MHz. Finally, an Intel 8041 running at 6 MHz, sometimes known as a I8X41, was used to control the cassette subsystem.