[asterisk-bugs] [Asterisk 0013209]: DTMF RFC2833 via SIP is not working

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=13209 
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Reported By:                ip-rob
Assigned To:                
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Project:                    Asterisk
Issue ID:                   13209
Category:                   Channels/chan_sip/General
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     feedback
Asterisk Version:           1.4.21.2 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
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Date Submitted:             2008-07-31 08:23 CDT
Last Modified:              2008-09-02 10:12 CDT
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Summary:                    DTMF RFC2833 via SIP is not working
Description: 
Using provider bandwidth.com which support RFC2833.  Configure outbound
trunk to use dtmfmode=rfc2833 and we receive double digits on a different
asterisk servers IVR.  American Express IVR does not accept any digits
(used main customer service line to test entering credit card number). 
Other IVR functions do not work.

Changing to inband works but inband should not be required by
bandwidth.com, they support rfc2833.

Configuration is using SIP devices and SIP trunks only.  A search in issue
tracker found similar problems in January of 2008 but no currently open
issues.
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 (0091966) blitzrage (administrator) - 2008-09-02 10:12
 http://bugs.digium.com/view.php?id=13209#c91966 
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After talking to Joshua Colp on IRC, he has explained that chan_sip only
has the capability to send DTMF with one method at a time, so if you turn
on rfc2833 it will only send rfc2833. But if there is inband DTMF coming
into the system and then trying to go back out via RFC2833, the channel is
suppose to mute that DTMF in the stream. If your phone is sending inband
DTMF, then Asterisk may not be muting it at all.

So in the scenario:

phone --inband--> Asterisk --rfc2833--> Level 3

It could be that the inband is getting passed through in addition to it
being detected and sent in the RTP packets out of band as well


As a test, could you use Monitor() and record the stream to see if you
hear the DTMF in the stream? 

Issue History 
Date Modified    Username       Field                    Change               
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2008-09-02 10:12 blitzrage      Note Added: 0091966                          
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