DTMF Tone Signaling Configuration

DTMF Tone Signaling Configuration

We send DTMF tone signaling in RFC2833 mode (out of band signaling).

DTMF are transmitted with RTP packets but are outside the audio stream. This seems to be the de facto standard and most SIP Trunk providers use this method.

We also provide a DTMF testing facility for customers.

DTMF Mode RFC 2833


The incoming data delivers DTMF signals out-of-audio using the RFC-2833 mechanism and the DTMF signals are sent separately from the actual audio stream.

The recipient party must support the corresponding delivery mechanism if DTMF tones are to be recognized and it is necessary to ensure endpoints are configured to deliver/receive DTMF using RFC2833.