PA speakers cut out, need to verify codecs

[Baumli]

We are fighting issues with our paging system not coming through clearly all the time. The user's message along with our wav files (buzzers for shift changes) seem to cut in and out at random times. I've tested with 2 different snoms, one on just the network to isolate if the speakers are the issue, and both outputs match exactly. So I was wanting to make sure that we are using the correct codecs. We are using a Patton 4960 for our SIP Trunk.

Under Settings>>MS_LOCAL_CODEC_LIST we have PCMU PCMA G722 GSM G729 OPUS
Is this correct? Or should we try something else?

Hearing back from Patton, they said "Just select PCMU PCMA which are the ones by default on the 4960."
So should I remove everything except for those two codecs in 3cx?

 

[ChrisC_3CX]

Can you provide more info: https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

Also, what do you mean you've tested two different snoms? Are you using the Snom PA1 and you have two of them? Does the issue occur even if you make a call to them from another internal extension as opposed to having them receive an external call that goes through the patton gateway?

Under Settings>>MS_LOCAL_CODEC_LIST we have PCMU PCMA G722 GSM G729 OPUS
Is this correct? Or should we try something else?

You should never modify 3CX parameters unless instructed to do so by a 3CX Engineer. If you do wish to change the code priority you should do so from "Settings >> Codecs".

 

[Baumli]

Here's our details:
3CX Version: Professional Perpetual 16.0.8.16
Server OS: Windows Server 2016
Is the 3CX Server Hosted and where: On-premises
IP Phone Make/Model/Firmware version, e.g. Yealink T46U version 108.86.0.20
Trunk Provider or VoIP Gateway Make/Model: Patton 4960

As for testing the snoms, both are attached to the network poe, one is tied to desktop speakers, one tied to the amplifier/speaker system. We have a buzzer wav file that lasts about 3 seconds. When it plays, sometimes it will cut in and out at different spots (same when someone pages), and on both snoms, the output matches exactly. Meaning both sets of speakers from 2 different snoms cuts out at exactly the same spots. It doesn't cut out the same exact way every time, sometimes its perfect, other times it cuts out in the middle, other times at the beginning, sometimes at several spots. So that rules out the snoms are bad, as well as the amplifier and speaker system, as well as the wav file.

So I wanted to verify that the codecs are correct, or if they could be changed to something else. It pretty much has to be either the 3cx or the patton, from the tests we've been doing.

We have a spare patton, going to do some testing with it.

 

[ChrisC_3CX]

I would actually recommend making a few test calls from an internal extension to remove the patton gateway and the pstn line from the equation completely.

Also, I have to be honest, I don't think codecs have anything to do with this as it's usually not the case with audio cuts. What usually comes into play is the network configuration.

If you manage to reproduce this with calls from an internal extension (say a webclient, ideally on the same LAN) what you can do as a simple test is record those calls and then compare the recording of a problematic call with what you actually heard, does it match? Depending on what you observe you should be able to narrow down where the problem might be.

 

[Baumli]

To clarify, all of our phones are internal voip phones. So if someone calls internal to internal, does that bypass the patton completely? Is the patton strictly for internal to external and external to internal?

 

[ChrisC_3CX]

Yes, calls from one extension to another do not go through the FXO gateway so that means it's completely out of the picture in this case.