Problem with overlapping MOH


First off, I am posting this here, because I suspect this is an Asterisk problem or at least something you can configure on Asterisk. So please do not be alarmed by the first time you read Trixbox…

We are shortly before deploying an extensive test setup with Trixbox. Unfortunatly there is one big issue, that is preventing me to let the users make phone calls.

All is working perfectly, unless the user is being put through to another device on the remote side of the call. A second after the remote MOH has started to play, the Trixbox MOH is kicking in. That would be no problem, but after the call is connected to the new remote party, I have only one way audio. The user hears the remote side, but not vice versa. Before the MOH the audio is working both ways. It seems that my SIP-Trunk is sending an INVITE to trigger the MOH on my side.

I have put the Trixbox in an own Firewall segment with “open gates” where everything is passed through.

I think it would help, to switch off the behavior, overlapping the remote MOH with its own one.

Any ideas?