Our school has a Dukane MCS350 mounted on the wall. The computer portion has apparently failed and I'm wondering how hard it would be to connect a Raspberry PI to the analog portion and just output sound that way. I'm good with the PI interfacing and programming but need to know more about the 2-wire card in there.

[Linked Image from i.imgur.com]

I think we can just disconnect everything but the PS, Amp, 2-wire card, and speakers, then use the PI as the controller and sound input. The 2-wire card doesn't really seem that complicated with only a couple of connectors. Does anyone know where I can get more board-level diagram of at least the pinout descriptions for these connectors? It seems the dense 40pin'ish connectors select which speaker to output to and then a master audio input is fed into the board. I don't have manuals

Way I figure, it wouldn't be too hard to make the PI control the 2-Wire board if I knew more about those connectors. Any direct help would be great or even a push in the right direction would be appreciated. We're trying to use the existing premise wiring and such without buying a new system.