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CUCM 6.1.5 and CUCM 9.1 Call Recording CODEC Issue

I have a call recording issue where if the CODEC agreed between an MGCP gateway and the IP phone is G711 call recording fails as it looks for an MTP (there are subs running XCODE in the MRGs for the devices in this scenario).  The traces seem to suggest that there is mismatch between the agreed DTMF.

When the call between the phone and the gateway is G729 then call recording works fine and doesn't request MT resource.


SIP traces show that the recorder (Verint Impact 360) responds with a SIP OK which contains options for PCMA, PCMU, and G729.

Call manager traces show that as soon as the INVITE is sent to the call recorder from the CUCM the request for MTP resource begins (i.e. before any media options are presented and even before the 100 TRYING is sent back)


The region setting between the phone and the gateways, in the failure scenario, is set to G711 and link loss type is low loss.  On CUCM 9.1 Ive set a CODEC preference list which I have tried g711 as the preference and then also G729.

The region setting between the phone and the gateway regions towards the region the call recording SIP trunk is in allows max. G711.


The question is, why when the call is set up using G729 there is no requirement for an MTP on the call recorded leg whereas when the call is setup with G711 then the CUCM looks for MTP?

  • IP Telephony
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To answer your question we

To answer your question we need to look at the traces  , please attach both the traces here.