Difference between revisions of "Fax over VoIP"

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# Asterisk does not support T38 very well.
# Asterisk does not support T38 very well.


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== Update 2009.12.08 ==
Digium anounced that old fax application/implementation is crap: http://lists.digium.com/pipermail/asterisk-dev/2009-December/041067.html
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== Update 2010.04.22 ==
http://www.venturevoip.com/news.php?rssid=2385


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Revision as of 20:33, 26 June 2013

Evil fax.png

Fax over VoIP is not reliable and does not work most of the time.

It is possible to get a nearly 100% rate in rare circumstances but there is a very very low chance of this.

The broad explanation lies in a technology mismatch between FAX and VoIP, as explained in Steve Underwood's article here.

Steve Underwood developed the SpanDSP package, which helped to implement FAX support into Asterisk, Freeswitch and other open-source VoIP platforms.

The T38 protocol is supposed to work reliable over VoIP, but the problems with this protocol are following:

  1. Different hardware vendors do not follow standards and T38 implementation on various hardware is mostly broken.
  2. Asterisk does not support T38 very well.




See also