[asterisk-bugs] [DAHDI-linux 0016389]: [patch] busydetect incorrectly hangs up incoming call due to incoming DTMF seen as busy pattern.

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=16389 
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Reported By:                alecdavis
Assigned To:                
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Project:                    DAHDI-linux
Issue ID:                   16389
Category:                   dahdi (the module)
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     acknowledged
JIRA:                        
Reviewboard Link:            
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Date Submitted:             2009-12-03 17:54 CST
Last Modified:              2009-12-06 04:30 CST
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Summary:                    [patch] busydetect incorrectly hangs up incoming
call due to incoming DTMF seen as busy pattern.
Description: 
We're using WCTDM FXO modules for an IVR application/voicemail to a legacy
PABX.

Users, and the legacy PABX sends DTMF digits, after dialing voice mail.

Users have these programmed into their phones, dial main number then
pause, then dial known extension. The legacy PABX sends DTMF sequences
immediately the call is answered, to advise VoiceMail that the call is from
inside/out, a forwarded call due to non-answer etc.

Asterisk see's these repeated tone on/off patterns as busy signal and
hangs up.
Having busydetect on is required, as with signalling=fxs_ls requires it.
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 (0114823) alecdavis (reporter) - 2009-12-06 04:30
 https://issues.asterisk.org/view.php?id=16389#c114823 
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uploaded dtmf_busydetector.diff.txt

These tests are with a PBX that initially sends DTMF to indicated status.

tested with:
 busydetect=no. After dialling in and seeing the DTMF arrive, then hangup,
approx 20 seconds later the channel hangup the call. This result was also
the case before the attached patch.

 busydetect=yes. After dialling in and seeing the DTMF arrive, then
hangup, approx 5 seconds later asterisk hungup the channel, If I didn't
hangup, call proceeded as normal. Without the patch, asterisk would hangup
the channel on the caller after the 4th DTMF digit, with busycount=4 and
busydetect=yes. 

Issue History 
Date Modified    Username       Field                    Change               
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2009-12-06 04:30 alecdavis      Note Added: 0114823                          
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