[twojciac]

Not only am I having an issue with DTMF and ViaTalk, but I have found that if once I attempt to send DTMF, the party on the other end can no longer hear me.

So if I dial into a number which requires me to Press 1 for English, it'll timeout and send us to the operator and they won't hear us. Here's the relevant config:

[viatalk]
insecure=very
qualify=3600
nat=yes
dtmf=inband
dtmfmode=inband
context=from-analog

I have changed the dtmf to auto, and dtmf mode to info, and I have had no luck either way. Any suggestions?

[twojciac]

I figured it out myself. Here's the info for anyone else researching a similar issue. I have Asterisk with Cisco 7960 SIP phones. The SIPDefault.cnf for the 7960s was set to allow out of band signalling which was affecting DTMF.

Here are the relevant working configs:

SIPDefault.conf

# Inband DTMF Settings (0-disable, 1-enable (default))
dtmf_inband: 1
# Out of band DTMF Settings (none-disable, avt-avt enable (default), avt_always
- always avt )
dtmf_outofband: none
# DTMF dB Level Settings (1-6dB down, 2-3db down, 3-nominal (default), 4-3db up,
5-6dB up)
dtmf_db_level: 3


sip.conf

[viatalk]

dtmf=inband
dtmfmode=inband
relaxdtmf=no

extensions.conf

;Force DTMF inband for voicemail
exten => 1111,1,SIPDtmfMode(inband)
exten => 1111,2,VoicemailMain


;Inserted a forced DTMF mode inband for inbound calls
exten => _1NPANXXYYYY,4,SIPDtmfMode(inband)