Hi The RFC says "The Internet Telephony gateway detects DTMF on incoming side and sends RTP packets instead of regular audio packets."
So the Gateway can negotiate as supporting telephone-event in SDP as: m=audio 8000 RTP/AVP xyz a=rtpmap:xyz telephone-event/8000 where 'xyz' is the dynamic payload type, since 'telephone-event' does not have static payload type defined. Regards Ranjit -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Troy Cauble Sent: Tuesday, June 15, 2004 4:33 AM To: [EMAIL PROTECTED] Subject: [Sip-implementors] RFC 2833 SIP/SDP negotiation questions RFC 2833 states that telephone-event RTP packets can be sent instead-of *OR* in-addition-to voice. Is it correct that negotiating telephone-event as one format in a media stream m=audio 8000 RTP/AVP 0 97 a=rtpmap:0 PCMU/8000 a=rtpmap:97 telephone-event/8000 implies the former ("instead-of"), while multiple media streams m=audio 8000 RTP/AVP 0 a=rtpmap:0 PCMU/8000 m=audio 8002 RTP/AVP 97 a=rtpmap:97 telephone-event/8000 implies the latter ("in-addition-to") ?? Which technique is usually used? In the latter case, would you expect the 8002 stream to send anything when no telephone-events were happening (normal voice)? Thanks, -troy _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
