I’ll confess that I am new to this part. It was dumped on me without warning and that’s OK. Time to learn a few things. I have a GM300 that is going to be a remote base and a cable purchased from eBay that is prewired for the GM300 side. I understand (I think) that TX goes RX, RX goes to TX, GRND to GRND – but now for PTT, COR and CTCSS. I wonder if some could push me over a cliff – I mean in the right direction. I have no documentation on the RTCM.

 

Thanks, R. Wayne

 

The RTCM connections are:

 

 

Pin #

 

2     MIC                                          BLU

3     PTT                                           WHI-BLU

4     PROGRAMMABLE OUTPUT     BRO

5     FLAT TX AUDIO                        GRN

7     GROUND                                  WHI-GRN 

8     PROGRAMMABLE I/O (COR ?)ONG

11   RECEIVE AUDIO                       WHI-ONG

14   PROGRAMMABLE I/O              WHI-BRO

15-16  Jumpered to enable internal speaker