One way audio, sometimes no audio - only started happening recently

[Alphabetic]

Hi Guys,

I now have two reports for two seperate customers with instances where they're experiencing (not all the time) one way or no audio.

Both installs are LAN with Debian running v16.0.1.273

Site A have Fanvil X5S and 6 (FW1.10.8)
Site B have Fanvil X4 (FW 2.10.0.6646)

Both use Voiceflex for their SIP trunks and both sites are using PoE with some use their phones for LAN to PC.

These were both installed a month or 2 ago and were fine. Voiceflex had an outage a week or so ago with degraded their service but has since being restored so i've asked them the question.

Are there any known issues reported to or by 3CX which may have been caused by a recent update or FW update? I've been away for the past 2 weeks so havent been monitoring anything.

It's also difficult for me to replicate the issue and the firewall checks are passing.

any ideas?

thanks.

 

[leejor]

Are the sets on the same LAN as the servers?
Are there audio issues only on trunk calls, or extension to extension as well?
Is it one way audio in the same direction? Which?
Is it when placing or receiving calls, or both?
After one of the calls, have you checked the 3CXActivity Log for any errors?

 

[Alphabetic]

Hi Lee,

i'll discuss "Site A".

Handsets are on the same LAN as the 3CX. Debian VM on Hyperv host with 2 vCPU and 4GB RAM.

Customer said they had called (via trunk) out today and the customer said they sounded like they were underwater and then the receiver of the call could no longer hear the caller but the caller could hear the receiver.

 

[JohnS_3CX]

If you don't see any indication in your logs and internal calls are fine, the first thing to do of course would be to find out if the issue is from the PBX side or the provider side.

You would have to catch it in the act with some captures (using tshark if you want to capture in the background)

Once you eliminate which side is working fine, you can focus the rest of your investigation on whatever remains.

 

[Alphabetic]

Hi John,

thanks for the reply.

One of Site A's symptoms have been one way audio on EXT to EXT calls.

 

[JohnS_3CX]

Ok so in this case you have confirmed internal calls with one way audio? You should set up tshark to see what happens during one or more of the problematic calls (especially if the problem is intermittent). You would have to enable PBX delivers audio on the extensions though to capture the RTP stream. IF the issue is point-to-point this option would also likely solve the issue. *777 and *888 echo tests that also have one way audio would mean you could isolate the connection between the PBX and the phone directly to be problematic

Usually for internal one way audio issues it will involve network problems, port issues, firewalls, that kind of thing, so I would start by ensuring the whole network layout and path from PBX to devices and from device to device is healthy.

For external calls, I would firstly run the firewall checker to see if it passes.

 

[leejor]

What Codecs are you using internally, and what is your providers preferred Codec? Codec issues don't usually manifest themselves with one way audio, but the "underwater" sound might be something to do with Codecs. The fact that there are internal and external issues, if the sets and the server are at the same location, may point to a network, or Codec problem

 

[Alphabetic]

Hi Guys,

just an update.

Site A - Rebooted network equipment and had no report from users. However, I had reoccurring reports from one user in particular. Swapped the handset, swapped the cable, same problem. Call recordings and trunk traces showed no problems in packets but the issue remained!

Turns out customer isnt used to the smaller handset and was covering the mic with their finger!

Site B also had the same telephone system so I will be having a word to see if this is the same cause!