DTMF not working on incoming or forwarded calls

[keithl]

RFC2833 (out of band DTMF) was created because with narrowband codecs DTMF won't work in band. Even with wideband codecs (G.711), it is not 100%.

FPL handles outgoing calls perfectly, allowing G.729 and 101 (RFC2833 audio/telephone-event) to be negotiated. As of spring of this year (it worked before that), on incoming calls, FPL only proposes G.711 and not 101, forcing only inband DTMF which I have found completely unreliable. This fact I, and many others, have reported in the "General VOIP Discussions" forum.

BUT! New news! I think I have narrowed it down for FPL. I tried call forwarding to another number and found out of band DTMF is lost at FPL at the PSTN (SS7?) level, not at the SIP level. It seems FPL does not forward any incoming (PSTN) out of band DTMF. FPL seems to use it internally (voicemail) and forward it only as in band.

With this new news, can you (FPL), please look at what was changed in spring of this year that causes incoming calls to have out of band DTMF dropped (or converted to inband) at the PSTN (SS7?) level?

[keithl]

bump