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Zonker's DNPG DECServer 90M+ Clues page
(updated: Jul 13, 2008, 12:13 am)

This document will provide information and links to various pages with information regarding the DEC Network Products Group (DNPG) DECServer products (mainly the 90M+). My hope is that this page will be useful for connecting these DEC devices various server and network gear.

I've had an 8-port unit to test for Serial BREAK, and it passed with flying colors (it only sends BREAK when you tell it to). This was a step back in time for me, because I 'cut my teeth' on older DECServer and DELNI gear in the 1980's. I'm glad to see the current line still provide LAT and other DEC service protocols as well.

RDECServer 90M+ Signals and wiring info...

The legacy DEC products were notable for their use of the Modified Modular Jack (also referred to simply as the MMJ). It is similar in appearance to the RJ-13 (where "RJ" stands for Registered Jack"), but the MMJ has an 'offset' locking tab. Look at the images below for a better understanding. While this prevented folks from plugging a phone line into a serial port, it is one more special connector for which you need to stock parts and termination tools.

Specialty cables for connecting your DEC MMJ ports to other things...

Since the MMJ is kind of unusual, most other vendors don't make cables to connect the the MMJ ports. But, if you have the termination tools, you can use these diagrams to make custom cables (and avoid the daisy-chained adapters). These diagrams only support data-only connections. You'll need to tell attached devices to ignore the Hardware Handshaking and Hardware Flow Control signal inputs.

DEC MMJ to Cisco Console cable
DEC MMJ to Cisco Patch Panel cable
DEC MMJ to Cyclades Cisco Console Server cable
DEC MMJ to Digi CM Console Server cable

DEC MMJ to IOLAN Console Server cable
DEC MMJ to MicroAnnex Console Server cable
DEC MMJ to Opengear CM Console Server cable
DEC MMJ to Xyplex Console Server cable

DEC MMJ to Sun T3 disk array console
Male RJ45 signal pinouts
Female RJ45 signal pinouts

DNPG has changed their name...

As of January 1, 2008, Digital Networks began operating under the name Vnetek Communications, LLC.. (That's what the DEC Networks Product Group website says. It appears to me, after reading their website, that Vnetek has been around a long time, and sells solutions hardware from a number of older vendors.) If you still have any VAX gear, or DECnet networks in your shop, the folks at Vnetek have hardware toi help you. I hope the old DEC Network Products Group folks are also still around to help you.

Unfortunately, with the overtaking of the DNPG website, we also lost the deep-link to the support documentation for the DECServer 90M+, as well as to the firmware information. I don't see any good support links on the Vnetek site yet.

I'm interested in feedback...

If you find any errors, have comments, or if you have additional information that you feel that I could include, please send email to consoles at Are you curious why I maintain these pages?

Useful DEC Links(URLs);

NOTICE: Most of the pages, articles, and tutorials on this website are copyrighted works. You may make 'deep links' to various pages. (If you let me know which page(s) you are linking to, I'll let you know if I move the page(s) during updates.) Please send me email if you wish to republish any material, or use it on your own website.

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Copyright 1996-2008, David K. Z. Harris, N6UOW   View David K. Z. Harris's profile on
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