I was also wondering about this; I just need to send fax from Linux via bluetooth phone, though - not receive them. So I thought I'd jot down my notes.
Turns out, there's a program
/usr/bin/fax - in Ubuntu, it's installed via
sudo apt-get install efax (which is kinda inconvenient for online searches, as "eFax" is also the name of a well-know commercial service website... (and "fax" in itself is bound to get you many poor search results)).
I finally found this thread that seem to talk about exactly this thing, though; and here it is:
sending faxes with t610 - gmane.comp.kde.devel.bluetooth / mailinglist for development of KDE utilities for bluetooth
Actually you can use
rfcomm bind /dev/frcomm0 <phone-bluetooth-address>
to bind the bluetooth device to /dev/rfcomm0. You can then use this device
as a modem, e.g sending AT commands etc.
A[s] I have a prepaid card, I can not send facsimiles, so consider this also,
wheter your provider allows you to send fax papers ;-) ...
Hehe, I also had a long conversation with the hotline of my operator just a
minute ago. For some reason I had to dial the fax number without
international prefix (+49..).
Well, this is my result - still problems with permissions, but it works.
efax also complained a lot about some non-existing lock file at first and I
had to create some strange directories first.
$ sudo /usr/bin/fax NAME='fred' DEV=rfcomm0 PAGE=a4 FROM='' send
/tmp/kde-fred/kdeprint_mRL9Bbit.nnn is up-to-date
efax: Wed May 12 16:16:30 2004 efax v 0.9a-001114 Copyright 1999 Ed Casas
efax: 16:32 opened /dev/rfcomm0
efax: 16:33 using Nokia 3650 Nokia Nokia 3650 V 3.16 in class 2.0
efax: 16:34 dialing T0891488297533
efax: 16:49 remote ID -> " +49 89 ********"
efax: 16:49 connected
efax: 16:56 session 196lpi 9600bps 8.5"/215mm any 1D - - 0ms
efax: 16:56 header:[2004/05/12 16:16 fred p. 1/2]
efax: 17:49 sent 20+2292 lines, 52762+0 bytes, 53 s 7964 bps
efax: 17:49 sent -> /tmp/kde-fred/kdeprint_mRL9Bbit.001
efax: 17:50 header:[2004/05/12 16:16 fred p. 2/2]
efax: 18:13 sent 20+2292 lines, 17649+0 bytes, 23 s 6138 bps
efax: 18:13 sent -> /tmp/kde-fred/kdeprint_mRL9Bbit.002
efax: 18:13 done, returning 0 (success)
But the quality of faxes really sucks badly. I still prefer a pdf via email ;)
So, apparently it can be done from the command line - but only if your mobile operator has that service for your subscription, I guess...