Seeing that board caused a little bit of a flashback. After searching a little I believe that is the control board for a MRS 804 LTR Repeater.
LTR is/was E.F. Johnson's version of trunked dispatch radio (also known a land mobile radio) and the MRS 804 was for the 800 MHz band. LTR used sub-audible signaling for trunk control and DTMF/call progress tones to patch telephone connections.
My second engineering job was a startup developing LTR compatible systems and we worked with Uniden. There were discussions of Uniden buying the startup I had worked for but E.F. Johnson executives interfered. Their interference cost the CEO and controller their jobs and E.F. Johnson was forced to buy the company for what Uniden had offered the investors.
Couldn't find any free schematics or manuals online for the MRS 804 but there were some for sale.
Hope that helps!
-Joe