[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. 
====================================================================== 
https://issues.asterisk.org/view.php?id=16665 
====================================================================== 
Reported By:                d_richards
Assigned To:                
====================================================================== 
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:              
====================================================================== 
Date Submitted:             2010-01-21 03:29 CST
Last Modified:              2010-03-03 22:47 CST
====================================================================== 
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.
====================================================================== 

---------------------------------------------------------------------- 
 (0118940) twilson (administrator) - 2010-03-03 22:47
 https://issues.asterisk.org/view.php?id=16665#c118940 
---------------------------------------------------------------------- 
Woah, d_richards. Calm down.  I don't think anyone was arguing with
you--lmadsen was just asking for the information required to solve the
issue.

Looking at the code in trunk, anyway, it does look like we match on the
name. I believe that rfc2833 dtmf is a dynamically numbered payload and
therefor some other device could use 101 for something completely different
than a telephone-event.

We just have to make sure that anything we do doesn't break other devices.
Standards are there for a reason and we try very hard to follow them.  If
it is possible to make other broken implementations work without breaking
compliant ones, we often will do that. It is just something that has to be
done very carefully--hence why lmadsen was asking questions. There
certainly is no need for vitriol. 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2010-03-03 22:47 twilson        Note Added: 0118940                          
======================================================================