Hard to tell much from the information given, since the cards don't have
any identifiers.
But was the the DMP-11 or DMR-11 which used coax? It could be one of
those. Max 1 Mb/s interface, also for network.
It's not a DMC-11, KMC-11, or DMR-11. I have all 3, and they look nothing
like that. In fact I am not convinced this is a Digital-made board.
-tony