Cracking open the Radio Shack TRS-80 CoCo

The connector for the expansion slot is on the left hand side of this picture, and brings out the main CPU memory and data buses, plus power and control signals, in a very similar fashion to the IBM PC's ISA slots. Unlike the PC there's only one slot here, but Tandy produced a four-slot expander.

Everyone had their own connector standards in the early 1980s. Here, Tandy uses DIN plugs for joystick, tape and printer interfaces. The large grey box with three holes is the TV modulator – the only form of video output on the CoCo – and the power supply is on the right.

Photo credit: Mark Kaelin/TechRepublic