Ohhh.. that is interesting. It is a strange backplane (the larger board and the riser) with the CPU/RAM board that plugs into the riser which also feeds power to the rest of the system via the AT power supply hookup on the CPU board.

Looks like you can upgrade the RAM for the onboard Trident video chip.

The barrel battery has already been removed on the CPU/RAM board.

What could these be? It's on a local auction site and the seller doesn't have any info on it.
Any ideas?

Sorry, these are the best I got.

Some industrial card most likely with analog-to-digital converters for measurements and controlling. Nothing you want to buy, really.

Thank you!