[asterisk-users] fax support

[Gordon Henderson]

On Thu, 22 Feb 2007, Rilawich Ango wrote:

> Hi all,
> I have read many forums and discussion groups talking about fax
> support in asterisk. Some of  them conclude that asterisk doesn't
> support fax.  However, some of them conclude that there is no
> relationship between fax and asterisk as asterisk will only pass the
> fax signal to the fax machine.  I have tried the fax in asterisk
> before but failed.  Anyone can give me some guideline how to make fax
> support with asterisk?

Search the archives for some scripts I posted a few weeks ago.

But, as shipped, asterisk doesn't have native fax support, but it can be 
patched in via the spandsp code, giving you 2 new applications: RxFax and 
TxFax. You can plumb an incoming answered call to RxFax and it will decode 
the incoming fax stream into a TIFF file which you can then process as 
required.

Asterisk does have the capability to listen to the incoming line for the 
fax startup tones though, so you can use this as part of an auto-attendant 
dialplan script to answer the line, listen for fax, if fax, then call 
RxFax or connect it to an outgoing analogue port with a real fax machine 
on it, or if not, play a message (if you know the extension, dial it now, 
etc.).

You really want the incoming stream to be a PSTN line though, trying to 
encode an analogue fax call over the interweb is "problematic" and prone 
to failure. If going down that route, I'd get your DID supplier to do the 
fax to email conversion for you. (Theres a plethora of them in the UK, 
don't know about elswhere though)

Gordon