DigiRig Mobile Rev 1.11, using AT-778/RT95 cable.
Linux detects CP2102N on /dev/ttyUSB0 and C-Media audio device correctly.
Radio PTT works when I manually short TRRS R2 to sleeve on the radio cable. The radio keys normally, so the cable and radio PTT path are good.
Python RTS and DTR tests execute without error, but the radio never keys. Testing all RTS/DTR combinations also does not key.
Metering the DigiRig board PTT pad to GND shows no state change when RTS/DTR are toggled.
Question: does this board require a PTT jumper/config change, or is the PTT output stage likely faulty?