-i, --irq argument
specifies the IRQ to use for the parallel port in
question. If this is set to something non-zero,
-t and
-c have
no effect. If your port does not use interrupts, this option will make
printing stop. The command
tunelp -i 0 restores non-interrupt driven
(polling) action, and your printer should work again. If your parallel port
does support interrupts, interrupt-driven printing should be somewhat faster
and efficient, and will probably be desirable.
NOTE: This option will have no effect with kernel 2.1.131
or later since the irq is handled by the parport driver. You can change the
parport irq for example via /proc/parport/*/irq. Read
/usr/src/linux/Documentation/admin-guide/parport.rst for more details
on parport.
-t, --time milliseconds
is the amount of time in jiffies that the driver waits if
the printer doesn’t take a character for the number of tries dictated
by the -c parameter. 10 is the default value. If you want fastest
possible printing, and don’t care about system load, you may set this
to 0. If you don’t care how fast your printer goes, or are printing
text on a slow printer with a buffer, then 500 (5 seconds) should be fine, and
will give you very low system load. This value generally should be lower for
printing graphics than text, by a factor of approximately 10, for best
performance.
-c, --chars characters
is the number of times to try to output a character to
the printer before sleeping for
-t TIME. It is the number of
times around a loop that tries to send a character to the printer. 120 appears
to be a good value for most printers in polling mode. 1000 is the default,
because there are some printers that become jerky otherwise, but you
must set this to '1' to handle the maximal CPU efficiency if you are
using interrupts. If you have a very fast printer, a value of 10 might make
more sense even if in polling mode. If you have a
really old printer,
you can increase this further.
Setting -t TIME to 0 is equivalent to setting
-c CHARS to infinity.
-w, --wait milliseconds
is the number of usec we wait while playing with the
strobe signal. While most printers appear to be able to deal with an extremely
short strobe, some printers demand a longer one. Increasing this from the
default 1 may make it possible to print with those printers. This may also
make it possible to use longer cables. It’s also possible to decrease
this value to 0 if your printer is fast enough or your machine is slow
enough.
-a, --abort <on|off>
This is whether to abort on printer error - the default
is not to. If you are sitting at your computer, you probably want to be able
to see an error and fix it, and have the printer go on printing. On the other
hand, if you aren’t, you might rather that your printer spooler find
out that the printer isn’t ready, quit trying, and send you mail about
it. The choice is yours.
-o, --check-status <on|off>
This option is much like
-a. It makes any
open(2) of this device check to see that the device is on-line and not
reporting any out of paper or other errors. This is the correct setting for
most versions of
lpd.
-C, --careful <on|off>
This option adds extra ("careful") error
checking. When this option is on, the printer driver will ensure that the
printer is on-line and not reporting any out of paper or other errors before
sending data. This is particularly useful for printers that normally appear to
accept data when turned off.
NOTE: This option is obsolete because it’s the
default in 2.1.131 kernel or later.
-s, --status
This option returns the current printer status, both as a
decimal number from 0..255, and as a list of active flags. When this option is
specified, -q off, turning off the display of the current IRQ, is
implied.
-r, --reset
This option resets the port. It requires a Linux kernel
version of 1.1.80 or later.
-q, --print-irq <on|off>
This option sets printing the display of the current IRQ
setting.