The radio now appears as a device in both audio lists — 'Radio (TCI
network audio)' — so the receive audio and the voice keyer can both take
the CAT link instead of a sound card. No virtual cable, no second card, no
Windows mixer between the recording and the air.
The transmit side reuses the exchange the tone probe established, with a
WAV in place of the sine: the radio asks, we answer with the next slice,
and it sets the pace. The message is converted once, up front, rather than
per frame — a voice message is a few hundred kilobytes, and resampling
inside a callback that has 21 ms to answer would put arithmetic on the
path where a late frame is a gap on the air.
The PTT is untouched by all this: the keyer keys before and unkeys after
exactly as it does with a sound card, so a transmission is bracketed by
the same code whichever way the audio travels. And the playback runs OFF
the CAT goroutine, since everything else about the rig goes through that
one place and a ten-second message would otherwise freeze the frequency
display and the antenna following for ten seconds.
Two refusals rather than silent failure. A radio that has gone away stops
being offered as a device at all, and a radio whose transmit audio source
is still the microphone is caught within a fifth of a second — a voice
keyer that transmits silence is worse than one that says why it will not.
Confirmed on a real SunSDR: the stream decodes and the test recording
plays back clean. So it can do the job a virtual audio cable was doing —
this wires it to the QSO recorder, which already accepts a pushed source
(the Icom network audio uses the same door).
The conversion lives here rather than in internal/cat: the radio's job is
to hand over what it sent, not to know that the recorder works in 16 kHz
mono. Three samples are AVERAGED rather than two of them dropped —
decimating by picking every third folds everything above 8 kHz back into
the voice band, and on a receiver that is hiss, which a QSO recording has
plenty of already.
Off by default, and applied the moment it is switched: it replaces a
sound card the operator has already wired up, and an option that needs a
restart to take effect reads as an option that does not work.
rouggy