I had a thought about this in the shower yesterday!
My buddies at Tekserve got their start in Macs by building the (Mac controlled) Directory Systems for the Rockefeller Center (yes the place with the ice rink!) Office Retail/Space in NYC. This might be a similar board for some kind of Video Based Display. In that case a Color Lookup Table would substitute for the, then unavailable, Color Macs/Toolbox routines. Sound and an external Graphics Output System, TTL or CGA, would make a world of sense. That would easily explain all the extra logic on board. Coupled with the RS-422 Connections, you could do a LOT with a Mac in any Graphics based Display, Signage, Directory, etc.
Dunno, that's just a WAG! :-/
My buddies at Tekserve got their start in Macs by building the (Mac controlled) Directory Systems for the Rockefeller Center (yes the place with the ice rink!) Office Retail/Space in NYC. This might be a similar board for some kind of Video Based Display. In that case a Color Lookup Table would substitute for the, then unavailable, Color Macs/Toolbox routines. Sound and an external Graphics Output System, TTL or CGA, would make a world of sense. That would easily explain all the extra logic on board. Coupled with the RS-422 Connections, you could do a LOT with a Mac in any Graphics based Display, Signage, Directory, etc.
Dunno, that's just a WAG! :-/