I have a tricky question.
I successfully use a remote GSM/SIP adapter, using A-law codec and connected as a trunk to freePBX to place calls over the mobile network.
Possibly due to a bug in its firmware, the GSM/SIP adapter has an asymmetric behavior regarding DTMF:
- from the mobile network to SIP, the DTMF are translated in RFC 2833.
- from the SIP to the mobile network, the only chance to have an IVR answering you is to set DTMF in-band (it doesn’t convert RFC28833 to DTMF).
So the question is:
In FreePBX or asterisk, is there any trick I set a trunk to accept RFC2833 inbound, but force in-band DTMF outbound?
T H A N K Y O U