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

# de(4)

DEC DC21x4x (Tulip) 10/100 Ethernet device

## NAME

**de** – DEC DC21x4x (Tulip) 10/100 Ethernet device

## SYNOPSIS

**de\* at pci?**

## DESCRIPTION

The **de** device driver supports Ethernet adapters based on the Digital Equipment DC21x4x based self-contained Ethernet chips. This includes, among others, the following models:

- Asante

  - Cogent EM100FX and EM440TX

  - DEC PCI DE435, EISA DE425, DE450, DE500

  - older Linksys 10, 10/100

  - SMC 8432, 9332, 9334

  - ZNYX ZX3xx

  This driver may support other cards based on the 21040 and 21041 Ethernet controllers, or the 21140\[A\], 21141, 21142, and 21143 Fast Ethernet controllers.

The **de** driver supports the following media types:

- autoselect

  Enable autoselection of the media type and options.

- 10baseT

  Set 10Mbps operation on the 10baseT port.

- 10base2

  Set 10Mbps operation on the BNC port.

- 10base5

  Set 10Mbps operation on the AUI port.

- 100baseTX

  Set 100Mbps (Fast Ethernet) operation.

- 100baseFX

  Set 100Mbps operation.

- 100baseT4

  Set 100Mbps operation (4-pair cat-3 cable).

The **de** driver supports the following media options:

- full-duplex

  Set full duplex operation for UTP port.

For more information on configuring this device, see [ifconfig(8)](/ifconfig/8.md). To view a list of media types and options supported by your card try **ifconfig** **\<device\>** **media**. For example, **ifconfig** **de0** **media**.

Note that the media types available depend on the particular card in use. Some cards are explicitly programmed to a particular media type by a setup utility and are not changeable.

The old “ifconfig linkN” method of configuration is not supported.

## DIAGNOSTICS

- de0: waking device from sleep/snooze mode

  The 21041 and 21140A chips support suspending the operation of the card.

- de0: error: desired IRQ of X does not match device's actual IRQ of Y

  The device probe detected that the board is configured for a different interrupt than the one specified in the kernel configuration file.

- de0: not configured; limit of N reached or exceeded

  There is a limit of 32 **de** devices allowed in a single machine.

- de0: not configured; 21040 pass 2.0 required (X.Y found)

  - de0: not configured; 21140 pass 1.1 required (X.Y found)

  Certain revisions of the chipset are not supported by this driver.

## SEE ALSO

[arp(4)](/arp/4.md), [ifmedia(4)](/ifmedia/4.md), [intro(4)](/intro/4.md), [netintro(4)](/netintro/4.md), [pci(4)](/pci/4.md), [hostname.if(5)](/hostname.if/5.md), [ifconfig(8)](/ifconfig/8.md)

## AUTHORS

The **de** device driver was written by Matt Thomas. This manual page was written by David E. O'Brien.

## CAVEATS

Since the 21040 is available on both EISA and PCI boards, one must be careful in how one defines the 21040 in the kernel config file.