The possible listen audio sources include four Dante receiver (input) channels, the stereo line input, and microphone audio for
sidetone. Three rotary level controls allow users to create their desired headphone mix.
I tried keying the Comm #1 mike to see if I could transmit on Button 2, which I had previously selected after calling Red Crown, but there was no
sidetone and no reply.
Depending on the com radio, you might not have a
sidetone (the sound of your voice as you key the transmitter), but this method can likely restore communications or at least be an aid for troubleshooting on the fly.
The DA9057 features a programmable LED backlight driver, backup coin-cell charger, touchscreen interface, voiceband codec with
sidetone, ALC (automatic level control), general purpose filter engine and 5-band equaliser.