Crackling Noise

[werdnap]

Hi, I have spent some time searching the forum but didn't find anything to cover my issue.

We run 3CX v10 in a 100 seat call centre. The system co-exists with a SIP based hosted dialler. We run on a gigabit LAN and our WAN (uncontended and low jitter) is no where close to saturation. The dialler works absolutely fine, no call quality issues. Our 3CX server never breaks into a sweat. We record the calls and the quality of the recorded calls is good. We dont have the facilities to run QoS.

The issue for us is that real time call quality on the 3CX system is poor - much crackling and broken speech. We use Yealink T20 phones or the 3CX softphone.

We dont really have any network data analysis expertise (eg Wireshark) so we have to deal with things on a trial and error basis. Any suggestions would be most welcome.

Many thanks, Andy

 

[leejor]

Is this just an external call issue, or does it happen on internal calls as well? One direction? Both? That answer may help you to narrow down where to look next. If possible, do some hardware swaps/elimination. Different make/model of set?

 

[werdnap]

Thanks leejor. We dont really make internal calls but I will check this out and report back.

 

[sigma1]

SIP Trunk or PRI, vocoder (codec)?
Recording means 3CX delivers audio... You should run wireshark on the server and capture some RTP, select voip and check out the call on 2 channels, play it and identify the source. If you have the noise on the INCOMING side in the recordings it is NOT anything post 3CX (meaning 3CX or the phones).