DTMF "SIP notify" support in asterisk


Our asterisk PBX is connected to a Cisco CM via SIP trunk
The Cisco people say that the asterisk must support DTMF signalling “SIP notiy”.
They say that the CISCO cannot send SIP info" or RFC2833.
Does asterisk support receivning DTMF as SIP notify ?

Thanks in advance!
/Dan Erik

yes, check asterisk.org/doxygen/trunk/Config_sip.html
or your local copy. The word you are looking for is dtmfmode

Thanks for your answer.
But which option from bellow is for DTMF via “SIP NOTIFY” (not SIP INFO).


Set default dtmfmode for sending DTMF. Default: rfc2833
; Other options:
; info : SIP INFO messages (application/dtmf-relay)
; shortinfo : SIP INFO messages (application/dtmf)
; inband : Inband audio (requires 64 kbit codec -alaw, ulaw)
; auto : Use rfc2833 if offered, inband otherwise

Which version of CUCM? I would expect all recent SIP software to support RFC 2833. Current Cisco documentation includes INFO and RFC 2833.

What is the RFC for DTMF via NOTIFY? A quick Google fails to find one.

According to:
cisco.com/en/US/docs/ios/12_ … #wp1038274

"…Cisco proprietary NOTIFY-based out-of-band DTMF relay."

You’ll need to choose a different method, other than NOTIFY, on your CUCM to relay DTMF to Asterisk.

Thanks alot for your answers!!

(its an old version 6.x of CUCM)


I’d be surprised if that is old enough to make a difference, although we haven’t had to pass RTP through Cisco’s.