[asterisk-users] Free Fax for asterisk

[David Backeberg]

On Wed, May 13, 2009 at 7:39 AM, Markus Weiler
<markus_weiler at mailworks.org> wrote:
> I wasn`t very conviced about Spandsp, after trying several versions it
> worked, but not well.

spandsp has been revised to the point that it's now at 0.0.6pre11,
released this month. I've had quite the opposite experience, that
newer versions are working better than previous versions for me.

> We are sending faxes via SIP. When sending faxes from our 1.6 Asterisk
> to our 1.4 Asterisk 50%+ Faxes failed.
> T.38 worked once then stopped I never found the right
> Asterisk-App_fax-Spandsp-dialplan setup again.
> I event patched the app_fax, which contained errors, just to get it working.
> Although I have to admit I installed it on our other Asterisk
> 1.4.17-BRIstuffed (Spandsp 0.0.4-test6) and it works just fine.

You don't say what any of the errors were, so it's hard to tell
whether you encountered bugs or just had configuration issues.

As to fax over SIP, you cannot use a compressed voip codec. It must be
G.711 and you must send faxes no faster than 9600bps. You should also
definitely turn off vad on any intervening voip appliances.

With the 1.6.0 series, regular app_fax, T.38, and the 0.0.6 SpanDSP
series I'm receiving near 99% faxes from real business customers.