[asterisk-dev] RxFax doesn't receive anything

[Jeff Gehlbach]

On Feb 6, 2009, at 9:25 AM, tylmann wrote:

> I'm afraid you really seem to be wrong. A friend of mine got it  
> working through SIP, but I can't see any difference between our  
> config's.

Your friend probably got lucky.  Fax over SIP in the traditional sense  
of transmitting the modem tones over SIP media is very hit-and-miss,  
usually missing when you most need it to hit.  You're right to use the  
alaw (G.711a) codec, but even tiny amounts of jitter or packet loss in  
the network can cause the transmission to fail or be cut short.  If  
you can get it to work reliably, that's great, but there are no  
guarantees.

In any case, the rxfax application that you're trying to use is not  
part of Asterisk proper.  It's part of a package called SpanDSP that's  
maintained at http://soft-switch.org.  Please go there to ask  
questions about rxfax / SpanDSP.  This list's charter is to discuss  
the development of Asterisk itself.  Questions about configuring and  
using Asterisk belong on the asterisk-users list, but you're likely to  
get another redirect to soft-switch.org if you post your question there.

The topic of faxing over IP-based technologies has been covered and re- 
covered many times.  Please read http://www.voip-info.org/wiki/view/Asterisk+fax 
  for a good discussion.

-jeff