SIP Trunk + MTPs config

Unanswered Question
Jun 8th, 2010
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Hello All,

I have configured a SIP trunk to a third party PBX, and it works using G711 always with MTPs.

I have tried to use G729 placing the SIP trunk in another region, but the call fails.

I think that the problem is that the MTPs (I have CCM MTPs, IOS Software MTPs and IOS Hardware MTPs) are only G711.

Can you help me with this config, so I can use G729 in the SIP Trunk?


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Jaime Valencia Tue, 06/08/2010 - 07:38
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This really depends on the version you're running, whether you can use early offer with G729 or not, but if you're going to use G729 then you do need an MTP G729 capable and the one from CUCM can't do this.

You should be able to use delayed offer with G729 if you uncheck the MTP required.



If this helps, please rate

jfernandorosa Tue, 06/08/2010 - 12:57
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Hello Cecilia,

The SIP trunk is configured in the CUCM ok? The connection is made by IP PBX, you may need to change any  parameter in it.


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