[cisco-voip] SIP Trunk from ISP DTMF issue

[Paul van den IJssel]

Hi all,

Currently I'm running a acceptance test on a SIP Trunk from our ISP.
Everything is working fine except the DTMF.

Setup:
[GenBand SBC] ---- [SIP Trunk into CUCM 7.1] ---- [Cisco Unity Express 7.0]

The SIP Trunk as well as the CUE are in the same region supporting only
G.711. On the SIP Trunk I've tried all different kind of DTMF configurations
(No Preference, RFC 2833 and OOB). We've tried to force the GenBand SBC to
only use RFC 2833 as well as the SIP Trunk. But this didn't work, not even
after we added a MRGL with MTP's.

Is there some sort of best practive to implement DTMF over a SIP Trunk? Is
there a way I can do some debugging on the CUCM/CUE?

Kind regards,

Paul van den IJssel
Digacom
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