RFC 2833 Transcoding
RFC 2833 defines an RTP payload that functions interchangeably with DTMF Digits, Telephony Tones and Telephony Signals. The Oracle® Enterprise Session Border Controller can monitor audio stream for in-band DTMF tones and then can convert them to data-based telephone-events, as sent in RFC2833 packets. This section explains how the Oracle® Enterprise Session Border Controller transcodes between these RTP-based telephone events and in-band DTMF tones carried by G711. DTMF tones can only be transported in non compressed codecs. The Oracle® Enterprise Session Border Controller supports two DTMFable non-compressed codecs: PCMU (G711µ) and PCMA (G711A).
Note:
The following line is added to SDP whenever telephone-event is added on egress: a=fmtp:101 0-15The following two scenarios describe when telephone-event to DTMF transcoding takes place:
