Atari 3600, original model number
Atari CX-9000 Video Computer System
Atari CX7800, two joystick ports on lower front panel. Side expansion port for upgrades and add-ons. Bundled accessories included two CX24 Pro-Line joysticks, AC adapter, switchbox, RCA connecting cable, and Pole Position II cartridge.
Atari CX7800, second revision. Slightly revised motherboard, added an additional timing circuit. Expansion port connector removed from motherboard but is still etched. Shell has indentation of where expansion port was to be.
Atari CX7800, third revision. Same as above but with only a small blemish on the shell where the expansion port was.