Noise at the beginning of a call

[edlentz]

I have a customer that has 25 T26 V7 phones behing a Freepbx system version 2.11. They are using a Grandstream GXW4108 for the phone lines. Occasionally on an outbound call we get what appears to be two touchtones playing simultaneously for the first 4 -6 seconds of the call when it is being connected. I have run TCPdump on the Freepbx, don't hear it there. I ran the Pcap on the Grandstream, not there. I have run the Pcap capture on the T26 and it isn't there, although there were some RTP packets out of sequence. (6%). I enabled the jitter buffer in freepbx (200ms), but alas it is still there. I say it isn't there meaning I do not hear the noise when I playback the audio through Wireshark.

Has anyone got any clue what might be going on here?

Thanks for any ideas!

[jolouis]

It's the GXW4108 causing your issue. We ran into the same problem a while ago with a customer. The problem is on certain versions of the firmware the GXW seemed to echo back the tone of the last digit or two that were dialed as the out. You won't hear it in the audio because the GXW is sending it as out-of-band DTMF signals to the PBX/phones.

We went through the troubleshooting process, ended up finally getting a syslog dump from the GXW showing exactly when the problem happened, and submitted everything to Grandstream. Unlike Yealink though they are pretty horrible at support, and despite 3 firmware releases since we had the initial problem it's never been solved. In the end we ditched the GXW and put in an AudioCodes instead, problem disappeared instantly.

I can't guarantee your situation is the same, but I would strongly recommend trying a better analog gateway first and seeing if that solves your issue.

[edlentz]

(01-30-2015 03:52 AM)jolouis Wrote:  It's the GXW4108 causing your issue. We ran into the same problem a while ago with a customer. The problem is on certain versions of the firmware the GXW seemed to echo back the tone of the last digit or two that were dialed as the out. You won't hear it in the audio because the GXW is sending it as out-of-band DTMF signals to the PBX/phones.

We went through the troubleshooting process, ended up finally getting a syslog dump from the GXW showing exactly when the problem happened, and submitted everything to Grandstream. Unlike Yealink though they are pretty horrible at support, and despite 3 firmware releases since we had the initial problem it's never been solved. In the end we ditched the GXW and put in an AudioCodes instead, problem disappeared instantly.

I can't guarantee your situation is the same, but I would strongly recommend trying a better analog gateway first and seeing if that solves your issue.

Thanks for the info!! Yeah I submitted a dump to GS some time ago. They denied anything was happening on their endWe have this issue at another location. Both are using the same GS model. I will see if I can get an AudioCodes to install

Thanks alot!