I am planning to deploy a fairly standard PSTN-dodging setup, like this: T1 - * - IAX2 - * - T1 In other words, two Asterisk boxes with T100Ps, interconnected with IAX2, used for bridging calls from one PSTN endpoint to the other. What makes this interesting is that on the receiving end, there is an IVR that isn't under my control, so DTMF has to pass between the boxes. I'd like to use GSM to save bandwidth, but I know DTMF won't survive anything less than alaw. Is there a way for the sending Asterisk to pick up DTMF from the inbound Zaptel channel, send it out-of-band across the IAX2 link, and have the receiving Asterisk synthesize the DTMF on the outbound Zaptel? I know all of the components (DTMF decoding, out-of-band transmission, and synthesizing) are there in Asterisk, but I don't know how to make them work together to accomplish my goal. Thanks, Mark
Steven Critchfield
2004-Feb-10 09:56 UTC
[Asterisk-Users] Sending DTMF out-of-band over IAX2
On Tue, 2004-02-10 at 08:53, Mark Johnston wrote:> I am planning to deploy a fairly standard PSTN-dodging setup, like this: > > T1 - * - IAX2 - * - T1 > > In other words, two Asterisk boxes with T100Ps, interconnected with IAX2, > used for bridging calls from one PSTN endpoint to the other. What makes > this interesting is that on the receiving end, there is an IVR that isn't > under my control, so DTMF has to pass between the boxes. > > I'd like to use GSM to save bandwidth, but I know DTMF won't survive > anything less than alaw. Is there a way for the sending Asterisk to pick > up DTMF from the inbound Zaptel channel, send it out-of-band across the > IAX2 link, and have the receiving Asterisk synthesize the DTMF on the > outbound Zaptel? I know all of the components (DTMF decoding, out-of-band > transmission, and synthesizing) are there in Asterisk, but I don't know > how to make them work together to accomplish my goal.It is there and just works. IAX doesn't let you try and send the DTMF inband. -- Steven Critchfield <critch@basesys.com>