Background noise from one end point

[crisicon]

Hello community

Posting this in hope someone can have some relevant info to share.

I have a customer in Australia with an overseas employee connected to the 3CX system - using 3CX softphone. We had some issues due to Internet connection being unstable initially.
After making sure the internet connection is good enoug to sustain VoIP calls, we are left with only one problem:
Calls between that employee and Australia suffer from background noise. Most calls are ok because the other end point hardware's noise reduction kicks in and calls are resonably clear, although you can hear sometimes the hiss caused by this issue.
With others, the noise is persistent and we would like to get to the botom of it.

I did some packet capture (using 3CX's feature because it is deployed in the cloud) and I can hear the noise ONLY on the RTP stream from this employee's 3CX softphone. You can actually see it clearly in the Wireshark RTP player - and there is a point where it disappears for a few seconds (!)



We replaced the hardware, hoping it was caused by something such as drivers or sound card, to no avail.

I am asking today the local IT to make sure sip_alg is disabled (if possible) but from what I researched, it's not going to help.

Questions:
1. What could cause this hissing noise in this setup
2. Is there a way to determine the cause

Thanks in advance
Cris

 

[JohnS_3CX]

Hi Cris,

Get everyone on the webclient, with USB based headsets (not analog) if possible. Calls must be webclient to webclient for this test. With this proposed method, we are checking:

- The internet connections of all those involved (including the PBX)
- The audio hardware they use
- The codecs taking part

PS: It's important to know whether any user has recordings enabled, as this will affect the outcome.

 

[crisicon]

Hi @JohnS_3CX

Apologies for the late reply - had a very busy period and failed to see the notification.
Will do the test in teh next few days and get back with results.