After going through the old storage room at my theater I found what I believe is an EDI Bijou Hand-Held Remote w/ 4 pin XLR.
We replaced our Bijou with an Element a few years back (Long story...) but we still have the EDI MX Dimmer racks and TSC control stations (for our house light controls). Because the theater was outfitted with entirely EDI Equipment, there are many 4-pin XLR inputs in our system labeled for a remote. I wondered if the HHR could be used as an interface to control the system without booting up the Element. The TSC Control Box we have in our booth has a 4-pin XLR input labeled "Remote", however when plugged in, the HHR just writes random characters to the LCD and none of the buttons will function (I have tried reseating the socketed IC in the HHR).
Another possible candidate is the four pin HHR labeled input on our DMX Panels, however nothing whatsoever happens when plugged in here, there is no power to the remote.
After all this, I have narrowed my problems down to two opposing conclusions: Either the HHR is Broken, or it does not function without a working Bijou Console and the HHR port on the wall is a extension bus that plugs into the back of the console.