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The DIP 40 ICs prominently on display are two ICL7109CPL 12 bit ADCs, to the left are a bunch of CD4051 8-to-1 analog multiplexers, a resistor network and a DB29 connector to the outside world, the yellow brick is a trim potentiometer of some kind.
To the right is the DIN41612 back plane connector, at the bottom are a bunch of 74 series ICs and a DIP switch array, presumably some glue logic to decode the ISA bus addresses from the back plane.
This is a digital I/O card, each of the industrial PCs has two of them installed.
In this photo, the back plane connector is on the left, the right hand side is yet another DIN41612 connector that connects to something outside the PC … somehow.
On the PC side, we have another TTL glue logic DIP cemetery, including a socketed PAL labeled "PWRDIO" (Power Digital I/O?). Presumably the PAL is used for address decoding (together with the jumpers at the top) and the data from the bus is simply latched.
The output from the latches is fed through a bunch of optocouplers , into an array of PBD 3548/1 driver ICs. Whatever the PC was controlling could probably draw a lot of current.
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