Codecs used by system ext. voicemail 9999

[Thiek]

Is there a way to adjust the codecs used by the 3CX voicemail system? With our SIP Trunk we cannot use the option "PBX Delivers Audio", if we do, the phone quality for all Yealink desk phones goes to crap, so we turned off PBX DA and set all desk phones to G722. Today, I was told any voicemail messages left by the customer are horrible (newly installed site). I ran tests and sure enough any message left, when played back, is not only in slow motion but very choppy and broken, you cannot understand the message - yes it's that bad which is odd. Does not matter if message is listened to by dialing into the voicemail system or send via email and listened to via a play back app. Under SIP Trunk settings I turned on PBX DA and this fixed the voicemail issue but now all live desk phone calls sound horrible. I'm hoping v18 will fix this but haven't got that far yet, no changes during holiday so v18 is still a few weeks out. Do I have any options I have overlooked?

• 3CX Version - v16
• Server OS: Win2016
• Is the 3CX Server Hosted: No
• IP Phone Make/Model/Firmware: Yealink T42S or T46S Fw. Version 66.86.0.5
• Provisioning Method: Local / VPN / STUN / SBC
• Trunk Provider: AT&T
• Has the Firewall Checker passed: YES

 

[leejor]

If you are calling into the voicemail system, then the PBX Delivers audio option (extensions) isn't going to do anything. It is meant to route audio, that would normally go direct, between sets, through the PBX. If the recording sounds bad even when sent as an email attachment, then I have to assume that it is being recorded that way, so there may be something else at play here.

I have yet to see 3CX have an issue with voicemail audio quality because of a Codec setting, but, I guess there is always a first time.

Is the audio quality bad when it is a message from an outside caller, or from an extension as well?
What Codec is used on your trunks?
Have there been any other call quality issues?
Did this just start, or has it always been this way?

 

[Thiek]

Internal ext. to ext. is ok, the message quality is decent. External calls are the issue, I'm calling in from my cell phone (Verizon) and my home phone (Xfinity). Having the "PBX Delivers Audio" turned on at the SIP Trunk Level does help, you can actually understand the message left yet the quality is not by any means good. You can hear the diff for yourself, files attached.

Codecs on the trunk, earlier when I check it was G.711 U-law and A-law, I was on holiday when someone else added them and did testing. So today I added G722 and moved it to the top, and G729 which is at the bottom. So G722, U-law, A-law, G729. I did not reboot the server after adding them, don't believe I would need to but just mentioning it.

This is a new site and SIP Trunk added about 3 weeks ago and yes we've had to work thru audio and DTMF issues which is why I mentioned v18. JohnS with 3cx support mentioned that improvements were made with how DTMF is handled. Employees started moving into the building 3 weeks back so not too many calls coming into the building where people are leaving messages. The Human Resource Mgr. said she noticed it a week ago when she arrived. As for calls going out or coming in, we found G722 and U-law to sound the best, as mentioned earlier, we set all desk phone to use this value.

 

[Thiek]

Beside the voicemail issue it appears overall call quality has degraded, outbound calls to the customer are good but calls coming in are beginning to sound like the messages left on voicemail; slow speed, broken up, static. At the SIP Trunk I tried different settings other than G.711 which I believe is the supported by SIP Provider. G722, G729, even Opus but nothing makes a difference. I also matched the codec setting under Setting>General so it matches with whatever I was using at the SIP Trunk. Why are there two places you can set codec values, does one override the other? I'm finding nothing in online help links. Also, when a codec value is changed is recommended to reboot 3CX?

 

[cobaltit]

You can double check, but to my knowledge, AT&T only supports two codecs, G.711U and G729 and they default to G729. I would remove all codecs but G.711U from the trunk and test.

 

[Thiek]

Thank you. After hours tonight I did more testing and tried G729, G711, and Opus. I set the codec value at the SIP Trunk, then under Settings>General, and then at the ext. level for the Yealink T46S phone I was calling into. I would reprovision and reboot that phone as well as reboot the server, did this each time I made a codec change. However, I could not find the right combo to provide clarity. Actually, at one point I believe opus was providing rather decent quality sound but I tried for better, couldn't obtain it, tried to go back to opus but whatever combination I used earlier I was not able to reproduce. Left it at G.711, this still sounded slow and slightly choppy but at least they could make out what the customer is saying. Oh, oddly, the audio going out is fine, its the audio coming into 3CX that stinks.

 

[ivank]

The choppiness points to packet loss rather than to a codec problem, you need to collect wireshark traces and look into the RTP stream coming from the provider.

 

[Thiek]

Thank you ivank, I believe I found the issue with bad audio. I did not realize that if recording is turned on for an ext. this is basically turning on the PBX Delivers Audio and we know for sure that at this site PBX DA degrades the audio. I started recording calls of a few exts. in order to test an issue with voicemail, the msg. left from an outside caller is so horrible you can't make out what was said. After turning off recording at the few extensions I was testing at the workers said calls were much better. Voicemail is still horrible, can't understand the msg. left by outside callers, inside calls are fine, so I believe this voicemail issue is related to PBX DA because the system is "recording" and basically turning on PBX DA.

I also installed the last v16 update "8A Final" , the FQDN Hotfixes, and I believe a template for Yealinks and now the DTMF issue is back. Certain IVRs do not recognize the DTMF from the Yealink phones. I'll up upgrade to v18 and see if this fixes this issue, and maybe it will fix voicemail, and hopefully nothing new comes up.

 

[Thiek]

Upgrading to v18 did not help the voicemail issue, any outside callers leaving a voicemail, the audio is horrible on playback. Its so bad we can't understand the message, we had to turn off voicemail for external calls. Is there any way to turn off "PBX Delivers Audio" on the voicemail ext.?

 

[NickD_3CX]

Upgrading to v18 did not help the voicemail issue, any outside callers leaving a voicemail, the audio is horrible on playback. Its so bad we can't understand the message, we had to turn off voicemail for external calls. Is there any way to turn off "PBX Delivers Audio" on the voicemail ext.?

Especially to Voicemail, PBX Delivers Audio should not make any difference.
At this point, I think the best course of action would be to contact your 3CX partner to look into this further with you as I am getting the feeling there may be something else going on here.

Then your Partner could look into it with 3CX Support if needs be.