I hope I understood this correctly and I can report the following results:
1) I plugged in the "receive" headphone side of a Sennheiser headset into TX Out on the RigPi.
2) I connected to the RigPi via my iPhone using Safari. Connected to the IC-756PRO3
3) I started Mumble on the iPhone. Connected to the server
4) Listening on the headset, I could hear myself talking in the presence of the iPhone.
5) When hitting PTT, I could continue hearing my broadcast. The radio went into transmit,
but no audio/RF went out. My meters recorded no output. Never-the-less, I could hear myself
when I went into transmit. A slight hum from the cellphone when PTT, but no difference
in the headset.
There were no issues as previously reported of the radio "clicking" or otherwise: of course, I had no RF out.
If I did this correctly, does this tell you anything about my issues?