[asterisk-users] POTS - Incoming Voice or Fax - How to tell?

[Gary]

Hi Folks -

This may sound weird - but here goes:

I live in Japan and on my home POTS line I have a Fax/Phone machine.

If I receive a fax, the thing automatically switches to 'fax mode' and
prints the fax.

If the call is a 'voice call', it sits there & rings until answered.

The above is very reliable and works okay.

Of course signalling differs in each country (and even by Telco supplier)
but my question is:

Basically, how does the machine know if the incoming call is a fax or voice
call?

If there's a way to tell..................

Is there a way (for example) to plug the POTS line into a FXS port then plug
the fax machine into the FXO port...  AND...

If the incoming call is a fax, let Asterisk route it to the FXO port to
print the fax.

If the incoming call is voice, have Asterisk send the call to one of the SIP
hardphones.

Of course, Asterisk would have to figure out what type of incoming call this
is.

Just thinking. - Is this do-able?

Thanks in advance

Gary Guthary