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I am trying to test out transcoding in our lab. I do not have any old Selsius phones to be able to use G723 to a 7860. I therefore thought to make a call from a POTS phone, through a 2621 to a Call Manager with a dial-peer having a CODEC of say G723ar63 and routing this pattern to another Call Manager, and on to a 7860 phone. Signalling works fine, but as soon as I try to answer the call - it disconnects.

Extra information:

1) I have no partitions/CSSs.

2) The call works OK if I remove the CODEC command from the dial-peer.

3) Both Call Managers have Transcoding resources (E1 in a Cat 6K).

4) I have used Trace (detailled and all flags) and can only see 'Trancoder Enabled' on one line and then later 'MediaManager - ERROR wait_AuConnectErrorInd' several times.

My only thought is that (and do I remember correctly) that the calling party has to supply the transcoding resource - which would mean that the calling device (the router) would have to be aware of the transcoding resource and perhaps would therefore need Skinny?

Cisco Employee

Re: Transcoding

I'll take a crack at this one.

I assume the 2 CallManagers are using an Intercluster Trunk. If not please say so.

If you want the call to be G.723 from the FXS port across the Intercluster Trunk through to the other CallManager and then have the transcoder convert the G.723 to G.711 on the 7960 phone, then this is what you would need:

On CM A (where the router is) set the Default Region to G.723. Both the Intercluster Trunk gateway device as well as the router gateway device should be in the Default Device Pool that uses this Default Region. So CM A only sets up calls using G.723.

On CM B (where the transcoder and 7960 are) setup 2 regions: The Default Device Pool should use the Default Region. The "WAN" Device Pool should have the transcoder resource in it, and the Intercluster Trunk gateway device pointing at CM A in it.


Default to Default should be G.711

Default to WAN should be G.723

WAN to WAN should be G.723

WAN to Default should be G.711

I think that should work.

Note that if CM A and CM B are in a cluster, then the transcoding resource needs to be registered to the CallManager that initiates the call, which would be A. So if that is the case, make 2 CallManager Groups, one with A as the primary and one with B as the primary, and make sure that the router and the transcoder are in the group where A is the primary, and the IP phone can either be in A or B.

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