Hi, I would like to improve my understanding of T.38. 1. What T38FAX_VERSION_0 or T38FAX_VERSION_1 in chan_sip.c means ? voip-info.org implies one has to change values in chan_sip.c to make it work. Shall I set T38FAX_VERSION_1 or leave T38FAX_VERSION_0 in global_t38_capability ? Source code says "This is default: NO MMR and JBIG trancoding, NO fill bit removal, transferredTCF TCF, UDP FEC, Version 0 and 9600 max fax rate" What does "Version 0" relates to in this aboxe line ? MMR and JBIG transcoding ? 2. A softphone like Zoiper is able to receive voice or fax calls. When setting those values (see bellow) in sip.conf, does it mean : "t38/udptl will be chosen if a fax signal is detected somewhere in the path. If none, then alaw would be picked" t38pt_udptl=yes t38pt_rtp=no t38pt_tcp=no disallow=all allow=alaw 3. How do you reload updtl.conf ? Regards -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.digium.com/pipermail/asterisk-users/attachments/20090209/4d551116/attachment.htm
David Backeberg
2009-Feb-10 02:48 UTC
[asterisk-users] What t38pt_udptl is ? Explain T.38 in 1.4
On Mon, Feb 9, 2009 at 4:23 PM, Olivier <oza-4h07 at myamail.com> wrote:> Hi, > > I would like to improve my understanding of T.38.I recommend you try out Asterisk 1.6 if you want to play with T.38. I DID get asterisk-1.4 working with fax, but I was having a lot of issues with faxes dropping in weird ways. All of those issues went away when I upgraded to 1.6. Don't waste your time like I did. app_fax in asterisk-1.6 is very, very nice and worked great for me. It works with traditional analog fax as well as T.38. I have to say I'm impressed and grateful for all who contributed to this. asterisk-1.6 also has a better SIP stack and other improvements. Rather than trying to get 1.4 working with this, I strongly recommend reading the directions at: http://www.voip-info.org/tiki-index.php?page=Asterisk%20T.38 to build asterisk-1.6 with app_fax support