Multicast on Polycom phones?

Has anyone been able to get multicast working on Polycom phones? If so, what’s the secret sauce?

Which model phone?

I think the typical ones support it, but i have a feeling its a matter of configuring the listening ip / port on the basefile. If you tell me what model and I have that model I can try some things tomorrow

This is a VVX410. Here is my current configuration:

Are you trying to send out using the polycom or to receive, or both? What can you do now regarding multicasting?

Just trying to receive on the Polycom. I’m using the Paging Pro module in FreePBX mostly but also testing with multicast paging buttons on other phones, both Sangoma and Yealink. All other listening devices work fine.

Any luck Jeremy? BTW, thank you for your effort to help!

Here is the work I did on it:

Multicast Interoperative Paging - FreePBX / Endpoints - FreePBX Community Forums

Seems to work fine with only one brand, but mix them up and it’s hit or miss (mostly miss).

Can’t say I have a problem, but only using pcm_mulaw mono 16 bit 8khz driven natively by ffmpeg with -f rtp to rtp://address:port

I aspire to fully understand what you just said sir, but unfortunately, today is not that day.

This might help: when I dial a paging group number from the Polycom, the Yealink picks up the broadcast and starts playing it. But when I dial the same paging group number from the Yealink, the Polycom gives no indication that it knows anything about the broadcast. If the problem were a codec, would it behave in this way?

Actually its not a broadcast, technically slightly different as a multicast, you offer up a stream on ip:port , any client can connect to that ip:port if they want to. you can test that with VLC using it’s stream concept , some phones will only allow connections that fit certain constraints, for telephony the lowest common denominator would be a mono 8khz channel sampled at 16000 per second encoded with one of the g711 variants .

See if VLC can hear what you are sending first, add phones one by one . . .

It’s not the Codec: Something is not meshing up - Here is the testing matrix I found using the Polycom Multicast paging settings as the default:

You might be able to submit a ticket to Yealink Tech Support - I had no devices under warranty so I could not.

I’m using the Paging Pro module in FreePBX to send the page, so I’m not sure how Yealink support could help. I’ll try sending the page from the Yealink phone and also from a Sangoma, and even from a Cyberdata paging server just to see if I can get the Polycom to answer from anything I have. I’m sure it has no bearing on anything multicast, but SIP paging to the Polycom works fine.

Still trying to wrap my head around this.

multicasting is hard to debug with the tools that Asterisk provides, I suggest you use wireshark/tshark to see what exactly is sent by the sender and thusly what is processed by the receiver for that connection


It is almost guaranteed that any multicast can only be seen by a device in the same network as the sender, multicast is NOT generally routeable over the internet, are the two devices so available to each other ?

Yes, they are on the same network.

I would start off with wireshark tapping your multicast_address:port

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