Unable to print with SerialPort

[Sebastian James]

>
> Hi,
>
> i am using cups-1.2.12 with Debian Linux-2.6.18,i have developed driver for my printer it's working fine with parellel port,
>
> when i am trying to print with serial port it's giving error like this what may the problem, let me know please.
>
> error_log:
>
>
> root$vim /var/log/cups/error_log
>
>
>
> I [30/Jan/2009:15:09:38 -0800] Job 130 queued on "ltp2001" by "guest".
> I [30/Jan/2009:15:09:38 -0800] Started filter /usr/lib/cups/filter/pstops (PID 3547) for job 130.
> I [30/Jan/2009:15:09:38 -0800] Started filter /usr/lib/cups/filter/pstoraster (PID 3548) for job 130.
> I [30/Jan/2009:15:09:38 -0800] Started filter /usr/lib/cups/filter/rastertoescpos (PID 3549) for job 130.
> I [30/Jan/2009:15:09:38 -0800] Started backend /usr/lib/cups/backend/serial (PID 3550) for job 130.
> E [30/Jan/2009:15:09:38 -0800] PID 3550 (/usr/lib/cups/backend/serial) stopped with status 1!
> I [30/Jan/2009:15:09:38 -0800] Hint: Try setting the LogLevel to "debug" to find out more.
> E [30/Jan/2009:15:09:38 -0800] [Job 130] Unable to open serial port device file "/dev/ttyS0": Permission denied

This line suggests that the user which the cupsd is run with doesn't have permission to send data to the serial device port, /dev/ttyS0.

Check the permissions on /dev/ttyS0 and amend them. On my debian etch system, permissions are:

crw-rw---- 1 root dialout 4, 64 2009-01-30 07:34 /dev/ttyS0

And cupsd runs as root, so I would be able to print to serial (though I don't, and haven't tested it).

To alter the permissions on /dev/ttyS0 you'll want to edit the relevant udev configuration in /etc/udev - have a look in permissions.rules

> I [30/Jan/2009:15:09:38 -0800] [Job 130] Backend returned status 1 (failed)
> I [30/Jan/2009:15:09:38 -0800] Saving printers.conf...
> I [30/Jan/2009:15:09:40 -0800] commptr=""
>