NOTE: Since version 1.27, the obsolete fax back end has been replaced by the
efax back end. If you are still using the fax back end, you should delete your
printer and create a new one.

Installing fax4CUPS is very easy:

0. Install efax (http://www.cce.com/efax/), HylaFAX (http://www.hylafax.org/)
mgetty-fax (http://www.leo.org/~doering/mgetty/index.html) or CapiSuite
(http://www.capisuite.de/). For HylaFAX you need also grep and sudo.

1. Install the man page.

2. Install the efax/hylafax/mgetty-fax/capisuite-fax scripts in the CUPS
back-end directory, for instance, /usr/lib/cups/backend/; you can look at the
first lines of the file for configurable parameters.

3. Install the PPD files efax.ppd/hylafax.ppd/mgetty-fax.ppd/capisuite-fax.ppd
in the CUPS model directory, for instance, /usr/share/cups/model, and create a
new printer using the a suitable back end (see the man page).

4. Make sure the appropriate log directory exists and it is writable by the
user running the back end (e.g., lp). For efax, it's /var/log/fax, for
mgetty-fax is /var/log/mgetty, for HylaFAX is /var/log/hylafax and for
capisuite-fax is /var/log/capisuit. (You can change them tweaking the
environment variables at the start of the back-end scripts.)

5. Make sure that the user running the back end has no-password sudo
capabilities; for instance, if lp is running the back end you can as a
first try run visudo and add the line "lp ALL=(ALL) NOPASSWD: ALL"
to /etc/sudoers (this is, of course, largely too permissive).

6. Restart the CUPS daemon (usually "service cups restart" as root will do the
job).
