[asterisk-users] Fax detection (Sangoma)

[Gordon Henderson]

On Mon, 2 Apr 2007, David Ruggles wrote:

> I have an FXS port and an FXO port on my Sangoma, can I detect inbound Fax
> calls on my FXO port and route them automatically to the FXS port (connected
> to a fax machine) while allowing normal voices to ring the main extension
> like normal?

Yes.

However, asterisk has to answer the call and listen in to see if it hears 
the remote fax machine squawking down at it first.

This means that the caller will be left in silence for a second or 3.

Then you'll need to send a message to the caller, or give them a ringing 
tone.

> I looked through archive but didn't see this exact question addressed.

Look harder, I've posted this before ;-) Or try the WiKi, the book, or 
elsewhere....

You need to tell asterisk to listen to faxes - you do this in zapata.conf 
- with the line:

faxdetect=incoming

What will happen then is that asterisk will listen in for the fax tone 
when it answers the call, so you need to Answer() the call, and (I've 
found) then wait for 3 seconds.

exten => incoming,1,Answer()
exten => incoming,n,Wait(3)

If the call is a fax machine, asterisk will automagically then goto an 
extension called fax in the current context, so I guess (I've never done 
this - I suck it in & email it) you could then:

exten => fax,1,Dial(Zap/4)
exten => fax,1,Hangup()

where Zap/4 was the fax machine which should be set to answer immediately, 
nd hopefully the call will then get bridged and life will be sweet.

Back up in the answering code, after the Wait(3) you then need to do 
something else - ring an internal phone, use 'auto attendant" or something 
else, but let the caller know that something is happening.

Gordon