The KMC-18 is a DTMF microphone with a lighted keypad, and is functionally equivalent to a KMC-18A in Manual Dial mode. KMC-18A is a fully programmable DTMF microphone equipped with 8 memories and 9 operating modes including Auto-Dial, Store & Send, and Last Number Redial functions. The KMC-18A can be used in either the Operating mode or Programming mode.
In the schematic for the KMC-18/A, there are four open jumpers, J1 through J4. The documentation does not indicate what these jumpers are used for. It might be interesting one day to either disassemble the code in the processor (if it's readable externally), or try to figure out just exactly what they do...