[Asterisk-Users] DTMF Simultaneous Inband and RFC2833 performed by Asterisk => Duplicate tones

[Kevin P. Fleming]

Max Glucksmann wrote:

> - RFC2833 standard configured on both end-points.

If this is the case, but the end sending DTMF _also_ puts it inband, 
then it is broken. This is an either/or setting; it's either inband or 
out of band, but not both.

Asterisk sometimes listens for inband DTMF even when RFC2833 has been 
specified because the SDP tells us what the peer wants to _RECEIVE_, not 
necessarily what it will send. There are devices out there that will 
tell us they want RFC2833 but send only inband... many devices are just 
broken and/or inconsistent.