PBXes - Print: RE: Answering party cannot hear us

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Posted by cyberdude on 23.02.2009 at 17:40:

Answering party cannot hear us

Lately, well for the last few months, we have been experiencing a strange problem. 3 out of every 5 calls we make the person answering the call cannot hear us but we can hear them answering. If we hang up and redial immediately the call gets answered successfully and the person can hear us.

This seems to happen for all destinations we are calling. Any ideas why this is happening? I can't see anything obvious in the logs. Could it be problems with the codecs? We are using G726 ulaw.

Posted by Diafora on 24.02.2009 at 15:48:

RE: Answering party cannot hear us

This sounds more like a NAT traversal issue, than a vocoder issue. Regardless of that I would disable G.726 in favor of G.729 & G.711u (ulaw).

What kind of SIP User Agent do you use to dial the call? Is it located behind a router, and if it is what type of router is it?

The destination numbers you dial are they PSTN numbers connected to traditional phone lines, or are they DID numbers linked to VoIP services?