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DTMF Supported By Cisco

Dear all,

I using :  - Call Manager

             - Router Cisco CISCO2911/K9 ,Version 15.0(1r)M16 , System image file is "flash0:c2900-universalk9-mz.SPA.152-1.T3.bin".

My Topology

CUCM -> Trunk -> Voice Gateway -> Trunk -> SIP Server ITSP.

I integrate my call manager with voice gateway with sip trunk to ITSP SIP Server, I have some problem with receiving DTMF in incoming call, my ITSP patner said that they send DTMF in RFC4733 inband. When I "debug voip rtp named-event" nothing comes.

But for outgoing call the DTMF work fine.

My question is does cisco router support for this DTMF RFC2733 type? If yes, is there any document from cisco that say it?

Please help me with this case.

Thank you.


Rising star

Re:DTMF Supported By Cisco

Yes it is supported on Cisco IOS Release 15.2(2)T1. Make you put the dtmf-relay rtp-nte under the incoming and outgoing dial-peers.

New standard and system keywords are added to the existing dtmf-interworking command under voice-service and dial-peer configuration modes.
Old Behavior: SIP INFO DTMF digit to RFC-4733 DTMF interworking is not supported.
New Behavior: The newly added standard keyword generates RTP NTE packets that are RFC-4733 compliant.
Additional Information:




HTH Regards, Yosh

DTMF Supported By Cisco

Hi Yashiel,

I already put the dtmf-relay rtp nte to the dial-peer.

here some my dial-peer confguration

dial-peer voice 102 voip

description dial to Mobile Phone

translation-profile outgoing 1

destination-pattern 908[1-9][1-9]T

session protocol sipv2

session target ipv4:

voice-class sip dtmf-relay force rtp-nte

dtmf-relay rtp-nte

codec g711ulaw

no vad

dial-peer voice 202 voip

description INCOMING

destination-pattern 3799

session protocol sipv2

session target ipv4:

incoming called-number .

voice-class codec 1

dtmf-relay rtp-nte

I also try to put the dtmf-internetworking with

voice service voip:

- dtmf internetworking rtp-nte combine with diall-peer incoming (rtp-nte, standard, system)

- dtmf internetworking standard combine with diall-peer incoming (rtp-nte, standard, system)

the result still empty.



VIP Mentor

DTMF Supported By Cisco

Can you do a test call and send us

debug ccsip messages..

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"opportunity is a haughty goddess who waste no time with those who are unprepared"

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DTMF Supported By Cisco

Hi All,

I already open TAC this issue but still no clue, so I decide to change to E1.

Now after I change my SIP Trunk to E1 and the problem is solved.

Thank you for all your response.

Thanks and Regards,


DTMF Supported By Cisco


I used the commands:"dtmf-interworking standard" under the two dial-peers (cucm/cube & cube/SP) and the DTMF tones were transmited/received fine from then on. The SIP SP is accepting only In-band tones for telephony events.

The "dtmf rtp-nte" is sending telephony event out-of-band but within the RTP session, which is not in reallity an in-band method.


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