---
name: "udl"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["freebsd", "openbsd"]
url: "https://new.carta.tech/udl"
---

# udl(4)

DisplayLink DL-120/DL-160 USB display devices

## NAME

**udl** – DisplayLink DL-120/DL-160 USB display devices

## SYNOPSIS

**udl\* at uhub?** **wsdisplay\* at udl?**

## DESCRIPTION

The **udl** driver supports USB display devices based on the DisplayLink DL-120/DL-160 graphic chip.

## HARDWARE

The following devices should work:

- Century Corp. Japan Plus One LCD-8000U

  - Century Corp. Japan Plus One LCD-4300U

  - DisplayLink USB to DVI

  - ForwardVideo EasyCAP008 USB to DVI

  - HP USB 2.0 Docking Station (FQ834)

  - HP USB Graphics Adapter (NL571)

  - IOGEAR USB 2.0 External DVI (GUC2020)

  - Koenig CMP-USBVGA10 and CMP-USBVGA11

  - Lenovo 45K5296 USB to DVI

  - Lenovo ThinkVision LT1421

  - Lilliput UM-70

  - Nanovision MiMo UM-710 and UM-740

  - Rextron VCUD60 USB to DVI

  - Samsung LD220

  - StarTech CONV-USB2DVI

  - Sunweit USB to DVI

  - Toshiba Video Dock

  - Unitek Y-2240 USB to DVI

  - VideoHome NBdock1920

  ## FILES

The device can process compressed data (Huffman pixel difference method) to reduce the USB payload. To generate the compressed data, the driver needs to load a Huffman table, which is stored in the following binary file:

- */etc/firmware/udl\_huffman*

  If the Huffman table can't be loaded, the driver will fall back to uncompressed mode.

## SEE ALSO

[intro(4)](/intro/4.md), [usb(4)](/usb/4.md), [wscons(4)](/wscons/4.md), [wsdisplay(4)](/wsdisplay/4.md)

## HISTORY

The **udl** driver first appeared in OpenBSD 4.6.

## AUTHORS

Marcus Glocker ⟨*mglocker@openbsd.org*⟩