---
name: "lpt"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["linux", "freebsd", "openbsd"]
url: "https://new.carta.tech/lpt"
---

# lpt(4)

generic printer device driver

## 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)](/ppbus/4.md) 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 Secondly, inb()/outb() calls have been replaced by ppbus function calls.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)](/ppbus/4.md) 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)](/lptcontrol/8.md) command.

Depending on your hardware, extended capabilities may be configured with the [lptcontrol(8)](/lptcontrol/8.md) 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)](/ppbus/4.md), [ppc(4)](/ppc/4.md), [lptcontrol(8)](/lptcontrol/8.md)

## 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)](/lptcontrol/8.md) when there is no printer connected.

This driver could still stand a rewrite.