[pulseaudio-discuss] Has anyone configured for IP Phone Group Paging (aka Multicast RTP, using uLaw or aLaw or G.722 codec)?

[Arun Raghavan]

On Wed, 13 Sep 2023, at 12:31 PM, Pete Holzmann wrote:
> Turns out that almost every IP phone out there can be configured to 
> send and receive one-button speakerphone "paging" functionality.
>
> This standard capability uses multicast RTP, with specific IP and port 
> configured for each Page group. Most phones can monitor several groups.
>
> I am thinking that the exact same functionality would make a wonderful, 
> simple, whole-house intercom/paging system. "Time for dinner!" etc :-D
>
> Has anyone configured PulseAudio to send or receive these signals?
>
> I'd love to set up so:
> - in-ceiling speakers can play the "paging' message
> - various devices with a microphone can be used to initiate a "page"
> - etc...
>
> Am I missing something in thinking this ought to be quite doable with 
> this package?

It's doable, but not necessarily out of the box. We do have a couple of modules to send/receive RTP, and we can even detect streams on your network using SAP, but this is currently limited to L16 (16-bit PCM) and Opus: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/blob/master/src/modules/rtp/sdp.c#L93

-- Arun