Re: pulseaudio module to mute other sources?

[doug <dmcgarrett@optonline.net>]

On 08/12/2015 10:46 PM, Joe Pfeiffer wrote:
> I'm reasonably confident there must be a better place to post this than
> this newsgroup, so answers telling me where to look will be just as
> welcome as any that address the question!  I'm a Debian user, so this is
> where I'm trying first....
>
> Is there a pulseaudio module that will detect when an audio source isn't
> silent, and mute other sources in that cases?
>
> It may be more clear if I describe my particular desire use case.  I
> have a ham radio, whose audio output I can plug into my sound card
> input.  I'd like to be listening to music, but when a call comes in on
> the radio have it mute any other audio.
>
> Any thoughts?
I suspect that your ham radio is VHF--2 meters, or possibly 440MHz, 
since you say "when a call comes in."
Therefore, the radio certainly has a squelch circuit. As a ham, you 
should be familiar enough with electronics
to find a voltage in the radio that switches level when the squelch is 
activated or deactivated. You can
buffer this voltage with a transistor or a digital comparator, and use 
it to control the music via a relay.

Hint: squelch circuits usually (but not always) are controlled by the AGC.

--doug, WA2SAY