Intermittent Audio Issue

[Ricky Horne]

Hi,

I have currently started having issues where our windows client users can no longer hear external callers but it seem the external callers can hear our windows client users.

This doesn't happen all the time but it is quite a lot. Maybe two calls an hour per user.

Windows Client Version: 15.5.12227.5
PBX Version: 15.5.15502.6

Windows OS: Windows 10 Pro
Softphone: Plantronics Blackwire 320

 

[YiannisH_3CX]

Hello @Ricky Horne

Is the issue only with calls from and to the provider? Do you face issues with extension to extension calls? Also are the extensions local to the PBX or remote?
Try running the firewall checker and see if all ports pass the test.

 

[Ricky Horne]

Its just on incoming calls. its not every time its every couple of phone calls.

Currently only affected extensions are local to the PBX. (All on same VLAN, I have 1 device on a separate VLAN that hasn't had the issue but calls are infrequent anyway).

Extension to extension seems perfectly fine had no complaints yet.

I haven't run the checker for a few weeks but nothing should have changed on the firewall side....

I am currently trying the PBX delivers Audio and changing the codec from GSM-FR to G729

 

[YiannisH_3CX]

PBX delivers audio can sometimes fix issues with audio routing if the endpoints are on a remote location or different VLAN so it might no help you in this instance. No harm in trying though.
I would recommend running the firewall checker when no calls are active to make sure everything is fine on that front and then make any further changes.

 

[Ricky Horne]

The codecs and PBX delivers audio hasn't worked.
I ran the firewall checker last night and everything was green.
I restarted all services on the PBX last night to see if that makes any difference but i'm out of ideas now...

 

[YiannisH_3CX]

At this point you will need to see if there is actually audio coming into the PBX for the affected calls. You will need to run a packet capture on the 3CX server most probably using T-shark as the issue is intermittent. Once the issue is replicated you will need to go through the capture to see if the communication is correct and if there is any audio coming into the PBX.
Are you using a supported provider or not?

 

[Ricky Horne]

I have run a packet capture on 3CX sever and viewed with Wireshark but if i am honest I am not 100% sure what i'm looking for to determine if audio was transmitted and received.

On the call I have tested the audio worked both ways so knowing what to look for would be advantageous.

We are not using a supported provider but the provider use Telappliant for their lines which is supported by 3CX.

 

[YiannisH_3CX]

If the call captured did not have an issue then you should see RTP traffic in both directions. To get familiar with using Wireshark for troubleshooting issues you can start by watching our academy presentation: https://www.3cx.com/3cxacademy/videos/advanced/basic-troubleshooting/

 

[Ricky Horne]

Hi, We have not had the issue since the Monday.
The only thing i did was restart all the services on the server.
I did check up on and BT outages and it seems there may have been issues out of our control causing this.

 

[YiannisH_3CX]

Glad to see you are no longer facing the issue. Keep an eye on it and let us know if it comes back.