[asterisk-bugs] [Asterisk 0013716]: [patch] Prevent false answer of channel when going off-hook

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=13716 
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Reported By:                alecdavis
Assigned To:                
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Project:                    Asterisk
Issue ID:                   13716
Category:                   Channels/chan_dahdi
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Asterisk Version:           1.6.0 
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:             2008-10-16 04:58 CDT
Last Modified:              2008-10-22 04:01 CDT
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Summary:                    [patch] Prevent false answer of channel when going
off-hook
Description: 
With answeronpolarityswitch=no asterisk answers channel soon after dialout
has started, or perhaps just finished. Causing Ringing for the caller to
stop, then silence for a while as the call is setup, then telco ringing is
heard and call proceedes as normal.
 
With answeronpolarityswitch=yes asterisk answers channel as soon as the
line goes off-hook. The user hears a very short Ring from Asterisk, long
silence as digits are dialled out and call is setup, then finally telco
ring is heard.
This is caused in our case because the line does a polarity reversal when
going off hook.

I have modifed wctdm.c that adds polarityignore in 3 sections of the code,
strcut fxo, wctdm_voicedaa_check_hook and wctdm_hooksig.

I'll upload for your comment, but welcome any advice if there is a better
way.
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 (0094119) alecdavis (reporter) - 2008-10-22 04:01
 http://bugs.digium.com/view.php?id=13716#c94119 
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Please remove code for comment wctdm.c, as this was done at a too lower
level, but worked well.

uploaded patch chan_dahdi.bug13716.diff.txt

This implements polarityonanswerdelay if answeronpolarityswitch=yes to
prevent false answering due to line reversal on seizure, and is already
used for hanguponpolarityswitch=yes to prevent prevent false hangups just
after answering.

Looking at the variable name, seems as though it was originally intended
for this, and the code that was already there should have been something
else, perhaps polarityhangupdelay or polarity_answer_to_hangup_delay

By using the same delay this avoided another confusing parameter being
used in chan_dahdi.conf.

Alec 

Issue History 
Date Modified    Username       Field                    Change               
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2008-10-22 04:01 alecdavis      Note Added: 0094119                          
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