[asterisk-bugs] [Asterisk 0016793]: T38 flow states HDLC carrier immediately down when writing TSI to fax, but were up

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=16793 
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Reported By:                rlr2maverick
Assigned To:                
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Project:                    Asterisk
Issue ID:                   16793
Category:                   Applications/app_fax
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     feedback
Asterisk Version:           1.6.1.14 
JIRA:                       SWP-890 
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): 1.6.1 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2010-02-09 09:10 CST
Last Modified:              2010-02-10 15:09 CST
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Summary:                    T38 flow states HDLC carrier immediately down when
writing TSI to fax, but were up
Description: 
Good morning,

our setup is based on asterisk 1.6.1.14 & spandsp 0.0.6-pre17. We're
always receiving fax with no error.

When sending we're experiencing a quite strange chan_sip codecs
negotiation, selecting ulaw (8kbit??? with fax @14400 ???) even if slin is
preferred and available.

At the first write (TSI) from asterisk to the channel remote side (fax)
we're encountering HDLC carrier down and the transmission never takes
place.

T38 nego can't proceed and fax is never sent.

Is there any experience to share ?

Indeed,
RLR
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 (0117964) rlr2maverick (reporter) - 2010-02-10 15:09
 https://issues.asterisk.org/view.php?id=16793#c117964 
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nice to meet you lmadsen,

the bug we're experiencing was submitted to further investigation these
days.

We found it is bound to 

488 Not acceptable here 

error message in reply to a T.38 reinvite provided by either fax/ata with
no audio codec (and no other codec), during initial channel mode switchover
from audio to T.38 only transmitting a fax file with SendFAX application
(app_fax.c).

We're using 1.6.1.14 brabnch with spandsp 0.0.6-pre17

In effects it sounds to be a chan_sip.c related problem during coded
matching evaluation not considering T.38 proto just and already engaged.
Logs will follow. 

Issue History 
Date Modified    Username       Field                    Change               
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2010-02-10 15:09 rlr2maverick   Note Added: 0117964                          
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