The key here is use of the dummy sink using module-null-sink.After starting this thread ( Remote Desktop Server: Best choice from official repo or AUR on Raspberry Pi 4 (4 GB RAM)? ), I installed nomachine from the AUR on 's recommendation, and had no issues with it while I also had a monitor plugged into the Pi. This appears to work and I don’t have output audio from the ham transceiver also on the 0utput of the USB soundcard going back to the radio’s mic. Pactl load-module module-loopback source=nx_voice_out.monitor sink=alsa_b-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo Next, I send audio from my Mac to the output of the USB soundcard to be input into the mic jack of my transmitter: This gets received audio from the radio’s headphone jack picked up by the nx_voice_out sink because dummy is now the default sink and the received audio is sent back to the speakers/headphones of the Mac. Pacmd load-module module-loopback source=alsa_b-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-mono sink=dummy Pactl load-module module-null-sink sink_name=dummy Instead I created a dummy sink, made it the default sink, and assigned the output of the USB soundcard to the dummy sink:

It also bothered me that we had both ouput and input audio on the output of the USB soundcard at the same time, this just didn’t seem right.

It seemed to me like there was potential for feedback. The problem with the way we were doing it meant that received audio coming from device alsa_b-C-Media_Electronics_Inc._USB_Audio_, the input of my USB soundcard, was being redirected to the output of the same soundcard, device alsa_b-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo. I believe I have found a better way to send and receive audio to and from my amateur radio tranceiver.

Nomachine for raspberry pi