My VKLink node uses a PRM80 for the RF gateway, and needed a wiring harness to connect it to the Raspberry Pi.

I’m using DSP for all audio detection functions, which simplifies things significantly.  As such, I’m only using four pins.

8: PTT.  This will initiate TX on the radio.

6:  Audio in.  This is the radio’s audio input.

10: Audio out.  This is the radio’s audio output using raw discriminator audio, so not subject to volume or squelch changes.

3:  Ground:  This is simply used as the common ground for the audio lines.

The wiring harness to interface it with a Raspberry Pi looks like this: