In search of Three Rivers PERQ 1 Keyboard

Title says it. It saddens me that in this day and age I have to call this out but: ? This is for use with an actual real PERQ 1, not a Raspberry Pi running an emulator, nor something I?m looking for because I like to collect only the steering wheels off vintage Porsches because they ?feel nice? or ?look cool? or will ?make me a better programmer.? Actually perhaps a better analogy involves elephants and ivory... but I?m now off topic. Anyway- cruelty free, no-poach, free-range use intended. Thanks in advance for any leads or on-topic discussion of the keyboard protocol to tide me over in the meantime... With all the time on my hands from the shutdown it?d be great to make this system whole and start down the long path toward restoration.