The following is a close up of the modifications made to the GE Master was made by W4UWH. The numbers on the Back panel are the DB 9 numbers on the right, and I do not use Pins 1 or 2. I sometimes use pin 4 for power control, it requires the addition of a reed relay and pot. I use the Computer Automated Technology (CAT) Output 1 to close the relay to switch between two power settings.
The following diagram show the connection of a CAT 1000 to the repeater and Doug Hall's RBI-1 Remote Base Interface.
I used a different Pin for Pin 4
The voltages shown above are for the 224.98 #1 on bench.
I could not get enough deemp audio so I hooked to the speaker. I added yellow wire for speaker aduio to pin 5 od DB9 to connect Cat 1000