[asterisk-bugs] [Asterisk 0016756]: app_fax doesn't receive fax with T.38

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=16756 
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Reported By:                viniciusfontes
Assigned To:                
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Project:                    Asterisk
Issue ID:                   16756
Category:                   Applications/app_fax
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     feedback
Asterisk Version:           SVN 
JIRA:                       SWP-845 
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:             2010-02-02 13:56 CST
Last Modified:              2010-02-04 09:35 CST
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Summary:                    app_fax doesn't receive fax with T.38
Description: 
When I try to receive a fax from a provider that supports T.38 using
ReceiveFAX() provided by app_fax.so, the fax transmission ends prematurely
with an error.

What happens (according to Kevin Fleming) is this:

"In this call, Asterisk sent a re-INVITE to T.38 mode
from audio mode, the provider accepted it, and then Asterisk
acknowledged it. Immediately afterwards, Asterisk sent a re-INVITE
*back* to audio mode, which the provider accepted (and included T.38
capabilities in their response). Because of this, the FAX reception
process failed since the T.38 session was destroyed."

For reference, here is a link to the original mailing list thread: 
http://lists.digium.com/pipermail/asterisk-users/2010-February/244136.html
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 (0117712) viniciusfontes (reporter) - 2010-02-04 09:35
 https://issues.asterisk.org/view.php?id=16756#c117712 
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Upgraded to Debian Lenny 5.0.4 (Kernel 2.6.26). Running Asterisk 1.6.1.14
compiled from source, spandsp 0.0.6pre17 (current release).

Now app_fax doesn't crash anymore, but fax reception is damn slow. I
transmitted a fax from an analog landline and the bitrate negotiated was
just 2400 bps. One page took about 5 minutes to be transmitted. Good news
is I got no errors at all.

What info could I provide to help find out why the bitrate dropped so
dramatically? 

Issue History 
Date Modified    Username       Field                    Change               
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2010-02-04 09:35 viniciusfontes Note Added: 0117712                          
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