Symptom
DTMF is not working for call flow:
Analog Phone-->(FXS port)-->2921GW-->(SIP)-->Any system with RFC2833 DTMF only and 101 as payload
Conditions
ringing from SIP side needs to come without SDP:
005616: *Jan 31 14:26:10.339: //12/082C02898020/SIP/Msg/ccsipDisplayMsg:
Received:
SIP/2.0 180 Ringing
Via: SIP/2.0/UDP 10.31.124.168:5060;branch=z9hG4bK72482
From: ;tag=15F138-1D6C
To: ;tag=293565~f2fc2704-4626-426a-acd1-6c53b2284c64-31456239
Date: Tue, 31 Jan 2017 14:27:10 GMT
Call-ID: B9B878E-E6F811E6-8025AD39-EDF3B699@10.31.124.168
CSeq: 101 INVITE
Allow: INVITE, OPTIONS, INFO, BYE, CANCEL, ACK, PRACK, UPDATE, REFER, SUBSCRIBE, NOTIFY
Allow-Events: presence
Server: Cisco-CUCM10.5
Call-Info: ;x-cisco-video-traffic-class=MIXED
Supported: X-cisco-srtp-fallback
Supported: Geolocation
P-Preferred-Identity:
Remote-Party-ID: ;party=called;screen=no;privacy=off
Contact:
Content-Length: 0
Workaround
*Make the SIP server on the other side to send 180 ringing with SDP if possible.
*Disable "progress_ind alert enable 8" from the voip dial-peer(s) involved on the call flow.
