Abstract: There are electronic instrumentation assemblies in which most of the hard wired circuitry and functions are very similar for a significant number of different applications yet each assembly for a separate application is fabricated as a separate unit. Applicants system includes a single electronic circuit assembly for all such applications including a large plug-in connector, and a much smaller faceplate assembly with a mating connector unit containing software in the form of one or more PROMs plus a limited number of discrete components. An instrumentation assembly for a particular application includes the correctly programmed faceplate assembly which is plugged directly into the front panel of the electronic circuit assembly. As compared with having a separate electronic assembly for each different application, the present arrangement permits the major part of the assembly to be a single assembled unit with a single part number, configuration control, assembly and test procedure etc.