Hi folks,

I want to do some testing of DTMF detection on PRI which is another beast.

My setup is 1.6.1, couple of SIP softclients and 2 Digium PRI cards. My PRI link is looping basically to myself.

I can make calls out the PRI interface without issue. They loop back into my simple autoattendant and is able to recognize and print the DTMF digits pressed in the console.

My external DTMF detector is not seeing the DTMF but that is another story. When I config DTMF=inband on my clients I can hear DTMF fine when calling just user to user without going through the PRI card. When I dial my extension that routes the call through the PRI interface and back again there is minimal if not broken DTMF between clients.

I have done alot of searching and am coming up empty here. Any guidance appreciated and I can post *.conf files as needed. Would simply like an easy way to generate a call and play DTMF across the PRI for other testing purposes.


What codec? Only G.711 (mu- and A-law) and some higher rate codecs will carry DTMF well in band.

Ya it was set to G711 and mulaw.

I used dahdi_monitor to record what was happening on the media after I changed DTMF to inband on my PRI card. The DTMF is there and clear as day but the SIP client does not play it through to the speaker properly/at all.

Anyways I should have used the dahdi tool from the start but you learn as you go. For those others struggling with DTMF on PRI consider using it as well as it can save the media stream to a wav file for your analysis!