In the process of integrating voice alarming via Twilio SIP trunking and the Ignition Voice Alarming module, everything going well except for the DTMF signalling (pressing keys on phone, can’t get past ‘press any key to continue’ voice prompt). I think there is a mismatch between supported DTMF signalling methods between my twilio sip trunk and ignition sip.
TLDR Does anyone know what DTMF signalling methods Ignition Supports?
My twilio SIP trunk documentation states that they support:
“Out of band RFC-2833 is supported. Out of band SIP INFO is not currently supported. In-band DTMF tones within the G.711 audio stream are passed-through in the audio stream untouched.”
Right now, my guess is that my DTMF keys are being passed-through in the audio stream which perhaps ignition does not support/can’t detect?
I attached a PCAP of a complete SIP call that doesn’t show any additional RTP/SIP packets other than the INVITE/RINGING/OK/ACK/BYE packets, which makes me assume that either Twilio isn’t passing through the DTMF or Twilio IS passing it through but Ignition can’t detect.
For what it is worth: I remembered a few things about similar issues, and looked at a Downloaded section of the Ignition Manual regarding Alarm Notification, Twilio Module. At page 23 of 79, they specify VOIP voice notification at step 4 (Add Alarm Notification Profile Step 1 Choose Type ) where you specify the address of your SIP gateway. At the end of that step, page 24 shows Status of “Registered with VOIP host”. If you are getting that message, there are a couple of things that may help ( if you have a P.O.T.S.* line ). One would be to look at a modem ( such as an older USR V.34 Voice/Fax/Data modem ) that includes Caller ID to see if that is getting through with the modem simply listening on the line. The same modem could be used to send any DTMF code locally to eliminate most issues that might occur over the phone line, involving impedance ( caller-on-hold detection). *P.O.T.S. is short for plain-old-telephone-line as in -48VDC supply, loop (not ground) start, residential current. I have seen cases where the system was sending over 20ma due to line card problems, yet this is pretty rare. The fix for that was to add some resistance to the line, not recommended without a technician to measure that the current was excessive or minimal ( which had caused extreme noise and random decodes ).
The problem was with my Twilio SIP Configuration, not Ignition. I needed to ENABLE ‘Media Settings - Symmetric RTP’ in Twilio.
There is a setting in Twilio SIP → General called ‘Media Settings - Symmetric RTP’ that re-routes the RTP based on where the remote RTP is coming from (the incoming ignition connection) instead of using the destination negotiated in the SDP session descrip protocol.
For whatever reason, there is a difference between those two RTP destinations, so DTMF keys (inside of the RTP media stream) were not being returned to ignition. Now they are, and the voice alarm call menus work great. Image of setting in twilio web below:
[quote="will, post:1, topic:27370"]
In the process of integrating voice alarming via Twilio SIP trunking and the Ignition Voice Alarming module, everything going well except for the DTMF signalling (pressing keys on phone, can’t get past ‘press any key to continue’ voice prompt). I think there is a mismatch between supported DTMF signalling methods between my twilio sip trunk and ignition sip.
TLDR Does anyone know what DTMF signalling methods Ignition Supports?
My twilio SIP trunk documentation states that they support:
“Out of band RFC-2833 is supported. Out of band SIP INFO is not currently supported. In-band DTMF tones within the G.711 audio stream are passed-through in the audio stream untouched.”
Right now, my guess is that my DTMF keys are being passed-through in the audio stream which perhaps ignition does not support/can’t detect?
I attached a PCAP of a complete SIP call that doesn’t show any additional RTP/SIP packets other than the INVITE/RINGING/OK/ACK/BYE packets, which makes me assume that either Twilio isn’t passing through the DTMF or Twilio IS passing it through but Ignition can’t detect.
Thanks for letting us know where the real problem was found. It looks like a tough problem to unfold, yet not for the next one who wonders and then searches for the DTMF/RTP passing in Twilio.
