[asterisk-bugs] [Asterisk 0017318]: [patch] FXS Polarity Reversal on Hangup or Answer

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=17318 
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Reported By:                armeniki
Assigned To:                alecdavis
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Project:                    Asterisk
Issue ID:                   17318
Category:                   NewFeature
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     assigned
Asterisk Version:           I did not set the version :( 
JIRA:                        
Regression:                 No 
Reviewboard Link:           https://reviewboard.asterisk.org/r/797/ 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2010-05-11 06:12 CDT
Last Modified:              2010-08-11 15:00 CDT
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Summary:                    [patch] FXS Polarity Reversal on Hangup or Answer
Description: 
FXS lines normally connect to a telephone.  However, when FXS lines are
routed to an external PBX or Key System to act as "external" or "CO" lines,
it is extremely difficult, if not impossible for the external PBX to know
when the call has been disconnected without receiving a polarity reversal
on the line.

DAHDI/Asterisk should have a feature to allow a setting someplace, perhaps
in chan_dahdi.conf, to allow a FXS channel to provide a polarity reversal
on channel hangup.
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Relationships       ID      Summary
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related to          0017724 [patch] Race condition in handling writ...
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 (0125853) alecdavis (manager) - 2010-08-11 15:00
 https://issues.asterisk.org/view.php?id=17318#c125853 
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armeniki:
What I forgot to say above, is to look for the consistant a=1 and h=1 in
the analog_answer and analog_hangup.

If they are not both '=1' for you FXS port, you won't get a polarity
reversal at each event.
a=1 on the FXS port indicates "Polarity will be reversed when remote party
answers"
h=1 on the FXS port indicates "Polarity will be reversed when remote party
hangs up" 

Issue History 
Date Modified    Username       Field                    Change               
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2010-08-11 15:00 alecdavis      Note Added: 0125853                          
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