> Has anyone ever figured out why the RC96 does NOT mute RX audio when
> the receiver is inactive?
>
> Looking at the schematic it appears that the rx audio mux switch pin
> of IC9 (4053) should, in theory (according to the schematic), control
> the audio gating. The switch control pin is tied to the "select 1"
> line, which is driven by the cpu (indirectly).
If I remember right, both the RC85 and RC96 behave this way. As you said,
it is likely that they never implemented the control in software. The
RC85/96, unlike many other controllers, let hardware logic do a lot of the
grunt work to un-burden the processor, as is evidenced by the way it does
audio gating. I did a modification at the delay board, possibily similar to
what you did but I don't remember exactly, to properly mute when feeding it
unsquelched audio.
--- Jeff WN3A
