[asterisk-bugs] [Asterisk 0018550]: [new feature] support for T.38 pass-through

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=18550 
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Reported By:                under
Assigned To:                
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Project:                    Asterisk
Issue ID:                   18550
Category:                   Channels/chan_h323
Reproducibility:            have not tried
Severity:                   feature
Priority:                   normal
Status:                     feedback
Asterisk Version:           1.6.0 - SECURITY ONLY! Test 1.6.2 
JIRA:                        
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:             2010-12-29 11:01 CST
Last Modified:              2011-01-11 17:44 CST
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Summary:                    [new feature] support for T.38 pass-through
Description: 
Using already done work on behalf of
https://issues.asterisk.org/view.php?id=12380 and
https://issues.asterisk.org/view.php?id=15285, I'm going to
prepare T.38 pass-though support for chan_h323.
This includes:
1) T.38 capabilities negotiation (as done in chan_sip)
2) SIP<->H323 T.38 pass-through
3) support for RxFax(), TxFax() applications.

I have already a patch that works with hylafax + t38modem +
RxFax()/TxFax().
I need to make more tests before posting it here.

I will prepare patch(es) for 1.6.0.21 (we use it in production custom
system).
I can provide support in case if anyone interested has issues during
tests.
However I think I won't be able to provide patches for other Asterisk
versions due to lack of time. But it shouldn't be difficult to merge to
other Asterisk version for anyone interested because chan_h323 is not
heavily developed during recent years.

Please let me know if anybody is interested in testing/using/reviewing.
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Relationships       ID      Summary
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related to          0012380 [patch] T.38 support for chan_h323 with...
related to          0015285 [patch] reworked chan_ooh323
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 (0130381) under (reporter) - 2011-01-11 17:44
 https://issues.asterisk.org/view.php?id=18550#c130381 
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Initially I tested with hylafax, but it's too buggy to rely on.
Therefore, for testing following setup has been used: 

1) 2 Asterisk boxes (AST1, AST2)
2) AST1 is in terminal mode. SendFax(), ReceiveFax() applications are
used.
3) AST2 is in loopback mode. Using Dial() application it sends calls back
to AST1.
4) calls are triggered with call files
5) Before and after SendFax(), ReceiveFax() in both directions voice is
played with SayNumber() application.

Following modes have been tested:

1) SendFax (AST1) ->  (H323/fastStart) -> Dial (AST2) -> (H323/fastStart)
-> ReceiveFax (AST2)
2) SendFax (AST1) ->  (H323/slowStart) -> Dial (AST2) -> (H323/slowStart)
-> ReceiveFax (AST2)
3) SendFax (AST1) ->  (SIP) -> Dial (AST2) -> (H323/fastStart) ->
ReceiveFax (AST2)
4) SendFax (AST1) ->  (H323/fastStart) -> Dial (AST2) -> (SIP) ->
ReceiveFax (AST2)

Results have been verified with Wireshark (checked switch to T.38 and back
to voice, ports and media streams), transmitted .tiff file was verified
also with openoffice. 

Issue History 
Date Modified    Username       Field                    Change               
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2011-01-11 17:44 under          Note Added: 0130381                          
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