Atari 2600 Game Cartridge Adapter for the ColecoVision Game Console - Dismantled for reference and curiosity
The Coleco ColecoVision game console was already graphically superior to the Atari 2600 and had a range of near arcade quality arcade clones written by heavy hitters such as SEGA and Konami.
Wanting to take a bite out of Atari's giant game market share Coleco created an adapter that enabled the ColecoVision to run Atari's 2600 ROM cartridge software range.
Atari challenged this in court but as Coleco had made their adapter with off the shelf components and none of the same core parts used by Atari, Coleco was awarded victory making the ColecoVision with the Expansion Module No. 1 attached very attractive system.
It's a surprisingly complex little chunk and at quick inspection looks like a kit built Atari 2600 with a pass through that connects to the ColecoVision's ROM cartridge port. As it wasn't an integrated module users had to unplug the game pads from the ColecoVision and plug them into the Expansion Module No. 1 to play games.