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LPT(4)		       FreeBSD Kernel Interfaces Manual			LPT(4)

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	Secondly, inb()/outb() calls have been replaced	by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 com-
     mand 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 implementa-
     tions.

     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.

FreeBSD	10.1		       February	14, 1999		  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | FILES | SEE ALSO | HISTORY | BUGS

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