NAME

       lpt — generic printer device driver

SYNOPSIS

       device ppc
       device ppbus
       device lpt

DESCRIPTION

       The current lpt driver is the port of the original lpt driver to the ppbus(4) system.

       One  purpose  of  this  port  was  to allow parallel port sharing with other parallel devices.  Secondly,
       inb()/outb() calls have been replaced by ppbus function calls.  lpt is now arch-independent thanks to the
       ppbus interface.  See ppbus(4) for more info about the ppbus system.

       The parallel port bus is allocated by lpt when the printer device is opened and released  only  when  the
       transfer  is  completed:  either when the device is closed or when the entire buffer is sent in interrupt
       driven mode.

       The driver can be configured to be either interrupt-driven, or to  poll  the  printer.   Ports  that  are
       configured to be interrupt-driven can be switched to polled mode by using the lptcontrol(8) command.

       Depending on your hardware, extended capabilities may be configured with the lptcontrol(8) command.  With
       an ECP/ISA port, you can take advantage of FIFO and DMA.

       In  order  to  retrieve  printer  info  from /dev/lpt0, just apply the cat command to the device.  If the
       printer supports IEEE1284 nibble mode and has data to send to the host, you will get it.

FILES

       /dev/lpt0                         first parallel port driver

SEE ALSO

       ppbus(4), ppc(4), lptcontrol(8)

HISTORY

       This driver replaces the functionality of the lpa driver, which is now defunct.

BUGS

       There are lots of them, especially in cheap parallel port implementations.

       It is only possible to open a lpt port when a printer is connected and on-line, making it  impossible  to
       run lptcontrol(8) when there is no printer connected.

       This driver could still stand a rewrite.

Debian                                          February 14, 1999                                         LPT(4)