ROBERTS
model(s) wire color pin number
RCB-10 Audio 2
  Ground 1
  N/C N/C
  Common 1
  PTT 4
  receive N/C
model(s) wire color pin number
R5CB-770 Audio 1
RCB-470 Ground 4
  N/C N/C
  Common 6
  PTT 3
  receive 5
model(s) wire color pin number
RCB-15 Audio 1
RCB-55 Ground 2
  N/C N/C
  Common 2
  PTT 3
  receive 5