CUCM SIP Trunk DTMF to First Class Voicemail

Unanswered Question
Mar 23rd, 2009

Has anyone done this setup? We're have issues off and on with DTMF not being recognized correctly and have tried all the DTMF methods on the CUCM 6.11 SIP trunk configuration.

The vendor is wanting one packet sent for each keypress and not a series of keypresses in one packet.

The question they asked me is to enable the feature on our side to send a series of packets for each keypress configured.

I have this problem too.
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Nicholas Matthews Mon, 03/23/2009 - 20:10

You may want to try KPML or SIP-notify on the voicemail application. By default, since RTP-NTE (2833) is via UDP unreliably, we send multiple packets for redundancy.


Erick Bergquist Tue, 03/24/2009 - 08:26


Is there a way to only do KPML (OOB) on the Call Manager side? The SIP Trunk settings are No Preference, OOB and RFC2833, or RFC2833.

Is it possible to do SIP-notify on CUCM or does KPML (OOB) cover that?

The vendors product prefers to see a series of packets for each key, every 400ms representing key down, and then stopping at key up. They keep going back to us changing the option to "enable a series of packets for each keypress" on the Call Manager.

Nicholas Matthews Tue, 03/24/2009 - 12:24


CUCM will use whatever is negotiated with the other side. Here's a pretty easy one - just try all of them, resetting between attempts.

If none work, you need to see what you can change on the voicemail system.



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