You can use
start_dtmf in a dialplan to enable in-band DTMF detection (i.e. the detection of DTMF tones on a channel). You should do this when you want to be able to identify DTMF tones on a channel that doesn't otherwise support another signaling method (like RFC2833 or INFO).
A, B, C, D tones
Make sure to expect (and handle) the DTMF tones
C , and
D; these are very rare nowadays but they are still possible to send (e.g., someone has an old device with the extra ABCD column). See DTMF for more.
start_dtmf line listed above starts the
start_dtmf application on this channel to allow for DTMF detection.
Do not use the
start_dtmf application and the mod_dptools: start_dtmf_generate application together. If both are running at the same time you will cause a feedback loop to occur within FreeSWITCH itself, such that a DTMF tone from a caller will result in repetitive DTMF tones being identified by FreeSWITCH.
If using in conjunction with
ring_ready, make sure that
ring_ready is called first or else it may not work.
This application uses Media BUG.