[asterisk-bugs] [Asterisk 0016665]: DTMF not detected at all from Sipgate despite TCPDump showing keypresses

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=16665 
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Reported By:                d_richards
Assigned To:                
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Project:                    Asterisk
Issue ID:                   16665
Category:                   Core/RTP
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     acknowledged
Asterisk Version:           1.6.2.1 
JIRA:                       SWP-775 
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2010-01-21 03:29 CST
Last Modified:              2010-03-23 16:29 CDT
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Summary:                    DTMF not detected at all from Sipgate despite
TCPDump showing keypresses
Description: 
V: 1.6.2.1

Issue is with incoming calls from ITSP 'Sipgate'. DTMF keypresses are not
detected when they enter Sipgate from the PSTN network, despite being
clearly visible with a TCPDump. There are some very slight differences in
the events:
(this may help to visualise:
http://www.fotobytes.co.uk/user22171/dtmf_debug.php )

WORKING DETECTION:
1... .... = Marker: True
Payload type: telephone-event (101)
..00 0000 = Volume: 0
Event Duration: 480

FAILED DETECTION:
0... .... = Marker: False
Payload type: Unknown (101)
..00 1010 = Volume: 10
Event Duration: 1280

Initially considered this to be config/Sipgate but after several weeks of
tweaking, changes, reading up and consultation with Sipgate this looks like
Asterisk could be to blame. Have tried with Linksys ATA and it detects the
DTMF coming in from Sipgate flawlessly, which tends to support the issue is
at least partially with Asterisk.
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 (0119774) sharpone (reporter) - 2010-03-23 16:29
 https://issues.asterisk.org/view.php?id=16665#c119774 
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I believe I've hit a similar issue in 1.4.30

RFC2833 DTMF is unreliable when volume is set to 10. In asterisk version
1.4.26 volume was set to 5 and was reliable. Since volume is the absolute
value of -gain dBm0 (according to the RFC) 10 is a lower volume than 5, (or
0 for that matter) and may be why some PSTN type equipment is having a hard
time understanding it. It would be nice if this was a configurable
setting.

I'm not 100% sure that volume is the issue, however in studying the packet
dumps, its the only difference I can see.

I will be rolling back to 1.4.26 since I know it works, and DTMF is
critical for our sales people being able to reach their prospects. 

Issue History 
Date Modified    Username       Field                    Change               
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2010-03-23 16:29 sharpone       Note Added: 0119774                          
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