[asterisk-users] Fax over IP ?

[Tim Nelson]

----- Original Message ----- 
> Hi all,
> Couple of things I would like ask, does Asterisk provides free
> license for FoIP (for 1 channel) or need to purchase it? Couple of
> years back, I was able to send and receive the fax using Digium T1
> card, in term of FoIP how can I able to receive fax from traditional
> telephone lines / T1 lines? As far my understanding, the
> functionality for FoIP is to send fax to email or receive fax from
> email i.e. using T.38 protocol.
> The thing I would like to know how I can implement this solution i.e.
> receiving fax via IP? Correct me if I'm wrong, while receiving fax
> from traditional telephone lines will the topology looks like as
> listed below;
> PSTN Lines --> Asterisk (mounted a T1/ analog card) --> IP -->
> Asterisk (receive Fax over IP)
> or else?

FoIP typically means the fax session traverses an IP link at some point, most commonly at the 'last mile'. What happens to the fax after that is up to your requirements. The faxes can be emailed out, stored in a web application, printed to a printer, etc. The possibilities are endless.

Asterisk does have a few options for faxing. Those are most notably:

1. Fax for Asterisk - Free license available for 1 channel, or paid licenses for 2+ channels
2. app_fax (I think this is the current module name) - Free fax module for Asterisk, no channel limit, based on SpanDSP
3. Hylafax+ and IAXmodem - Most complicated method of fax setup, but most robust and reliable (in my testing). Would require use of Asterisk 10 with T.38 gateway functionality for proper fax reception.

Just keep in mind raw fax audio over VoIP is a bad idea, see here: http://www.soft-switch.org/foip.html

If you can provide some additional details on what you're planning to do, we can give more info.

--Tim