Does anyone here recognize this board? (Photos attached)
It looks like it was some kind of wall or bulkhead mounted control panel. It's got 16 alphanumeric LED displays, a keypad, and a serial port.
It appears to have been made by Burr-Brown (name in silkscreen which I overlooked earlier).
I disconnected the on-board serial line drivers (not EIA-232, maybe some multidrop serial) and hacked on an FTDI USB/serial bridge.
One of the 6522 timers is used to generate the BRC for the 6850.
I reverse-engineered enough of it to port the Apple ][ monitor and Integer BASIC to it.
Joe