CUPS Fax Backend Howto?

[Tilman Schmidt]

Hello Forum,

I am maintainer of a Linux ISDN driver. (drivers/isdn/gigaset)
One popular application for this driver is sending and receiving faxes via the program capifax. (http://capifax.v3v.de/)

Capifax comes with a shell script for integration with CUPS which is pretty awkward to use: it must be run in the background from an X session in order to listen on a TCP port which CUPS can address as a network printer, and then pops up a dialog via zenity to ask for the destination fax number. All other parameters must be set as variables in the script itself.

A more natural solution would be a capifax CUPS backend connecting capifax directly into CUPS, like fax4CUPS does for some other fax programs. I tried to create such a backend for capifax but hit some obstacles. The current state of my work is available for download at
http://www.phoenixsoftware.de/~ts/capifax4CUPS.tgz
I would be grateful for comments on how to address these problems:

1. When printing from the command line through the "lp" command, specifying the destination number works fine, either as the job name or as option "phone". This does not work when printing from an application. The "pseudo-Foomatic driver" section at the end of the PPD file doesn't seem to have any effect.

2. Printing from the command line only works for PostScript files. Other formats seem to get sent to the backend without conversion, making GhostScript barf. I expected CUPS to take care of that, converting everything to PostScript before passing it to my backend.

Other comments on how to improve that backend or pointers to relevant documentation are of course also very welcome.

aTdHvAaNnKcSe
Tilman