This came from a box of old computer equipment. It's two boards joined together by stand-offs and several wires. Only one of the boards has a bus connector edge.
Update from a reader:
The large IC (COM2502) is a standard 40-pin UART. Look up the Western
Digital TR1602 for pinout and function. Quite a number of manufacturers
made their own 40-pin UARTs that, while having different pin names and
sometimes different speed capabilities, were almost always pin-compatible.
This is the "top" view. Click the image for a larger version. |
The outward side of one board is labeled "Modem 80".
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The other board is a "Serial TTL" that was apparently used
with a cassette recorder to load and save programs.
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This is the largest IC on the serial board.