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DTMF not being passed for PeterConnects, but does work for Contact Center Express

Tom Ribbens

I have this strange issue, when inbound calls go to PeterConnects, the menu choices don't seem to work. This does work internally. When dialing in to a different number in the range that goes to Contact Center Express, DTMF does work. 


I tried debug voip rtp session named-event, and I indeed do not see any DTMF messages when calling the PeterConnects number. Calls to UCCX and PeterConnects are routed identically on the gateway though, so I don't understand how this can happen.

1 Reply 1


Hi Tom,


Please explain the calls flow for example PSTN>>Gateway(h323/mgcp)>>ccm>>ipcc(CTI rp)

UCCX can only support OOB afaik

(assuming above call flow)

so first we need to see if the dtmf is there on the router. if it is inband than we need an MTP to convert it to OOB. Please add an MTP in the MRGL of the cti route point/ports. Make sure if we are using g711ulaw tha the software MTP will work but if the stream is G729 than we need  MTP configured to use G729.



"Cisco Unified CCX CTI ports are notified of caller-entered digits (DTMF input) via JTAPI messages from Cisco Unified CM. Cisco Unified CCX does not support any mechanism to detect in-band DTMF digits where DTMF digits are sent with voice packets. In deployments with voice gateways or SIP phones that only support in-band DTMF or are configured to use in-band DTMF, an MTP resource must be invoked by Cisco Unified CM to convert the in-band DTMF signalling so that Cisco Unified CM can notify Cisco Unified CCX of the caller-entered digits. Be sure to enable out-of-band DTMF signalling when configuring voice gateways in order to avoid using the previous MTP resources.

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