Hello,
I have recently been struggling with DTMF relay configuration in which the provider has issues with in-band DTMF transport and has requested DTMF's to be delivered out-of-band. Examining the SIP INFO and the SIP NOTIFY methods for out-of-band DTMF delivery, has led to the following predicament.
As per this link
http://www.cisco.com/en/US/docs/ios-xml/ios/voice/sip/configuration/15-mt/voi-sip-dtmf.html#GUID-901BED51-E8B2-4994-AC38-875E8A10D7C9
"NOTIFY-based out-of-band DTMF relay is a Cisco proprietary function."
While on the other hand, looking at another Support Community article at
https://supportforums.cisco.com/community/netpro/collaboration-voice-video/ip-telephony/blog/2013/05/27/understanding-sip-dtmf-options-supported-by-cucm
we have CSCse50733 according to which "CUCM and IOS gateways can receive SIP INFO (RFC 2976) messages for DTMF but cannot generate them"
Does this mean that RFC-based out-of-band DTMF generation is currently not supported at all by Cisco voice gateways?
Kind regards,
Miroslav
