DEC Ethernet Transceivers

DEC Ethernet Transceiver Models

H4000 Ethernet Transceiver (Thickwire)

Year of introduction: 1982

You cannot disable the Heartbeat feature of the standard H4000 Ethernet Transceiver, there is a special version (H4000-BA) without Heartbeat available in case you need that.

H4000 with Inclusive Tap

H4000 with Inclusive Tap

The H4000 Ethernet Transceiver with Inclusive Tap was the very first Ethernet Transceiver from DEC.

It has got two drawbacks:

• If the tap pin gets damaged, the whole unit is inoperable and cannot be repaired.
• It is very inconvenient to mount the unit to a Thickwire segment difficult to access, e.g. located in a ceiling plenum.

H4000 with Removable Tap

The H4000 Ethernet Transceiver with Removable Tap is an improved version of the model with a fixed tap.

You can tap the cable using the removable tapping unit (which is much smaller and lighter than the complete unit) and attach the rest of the unit when the tapping is done.

If the tap gets damaged, you can use a replacement one.

<Picture of an H4000 with Removable Tap>

H4005 Ethernet Transceiver (Thickwire)

Year of introduction: 1988?

<Picture of an H4005>

DESTA Thinwire Ethernet Station Adapter

Year of introduction: 1986

Early DESTA

The early DESTA (REV A) is a H4005 with a modified top assembly carrying a female BNC socket.

You can replace the BNC top assembly with that of an H4005 and thus use the early DESTA with Thickwire Ethernet.

On the other hand you can use the top assembly of an early DESTA to use an H4005 for Thinwire Ethernet.

<Picture of an early DESTA>

Late DESTA

The late DESTA (REV B) is housed in a slightly smaller box and the BNC socket is fixed.

<Picture of a late DESTA>

H3350 Twisted Pair Transceiver

Year of introduction: ?

<Picture of an H3350 Twisted Pair Transceiver>

DECXM Thinwire Transceiver

Year of introduction: ?

<Picture of a DECXM Thinwire Transceiver>

DETPM 10BaseT Transceiver

Year of introduction: ?

<Picture of a DETPM 10BaseT Transceiver>

Removable Tap Assembly Instructions

from: EK-H4005-IN-002 H4005 DIGITAL Ethernet Transceiver With Removable Tap Assembly Installation Card

Tap Installation Tools

Not included in tools set; typically good for 10-15 installations

Tap Installation Tools

Tap Assembly

Tap Assembly (DEC P/N 12-24664-01)

Preparing Tap Body

Preparing Tap Body

Install braid terminators into tap body.

Positioning Coaxial Cable and Assembling Tap

Preparing Tap Body

Steps:

1. Position tap body on black band that is on coaxial cable.
2. Slide clamp assembly onto tap body.
3. Install clamp screw and tighten with hex wrench.