As far as I know this board is used only on System 24 for driving games (Hot Rod and Rough Racer) and golf games (Jumbo Ozaki Masters and Dynamic Country Club).
It handles analog inputs (e.g. steering wheels, gas and brake pedals, etc.).
I've been looking for one for a very long time and finally took the decision to reproduce it. Still it wasn't easy to find an original board as model for my reproduction.
Once again a German collector came to my rescue and lent me his board:
And here's my CAD reproduction:
It's quite expensive to build due to ICs used being dropped for a long time (D4701, M5203).