Xref: utzoo comp.dcom.lans:1480 comp.protocols.tcp-ip:3838
Path: utzoo!attcan!uunet!mcvax!ukc!its63b!epistemi!edai!tsa
From: tsa@edai.ed.ac.uk (Tom Alexander)
Newsgroups: comp.dcom.lans,comp.protocols.tcp-ip
Subject: Re: Looking for comments on the 15-pin ethernet connector
Message-ID: <126@edai.ed.ac.uk>
Date: 16 Jun 88 13:57:43 GMT
References: <3352@phri.UUCP>
Organization: AI Edinburgh Uni
Lines: 53

From article <3352@phri.UUCP>, by roy@phri.UUCP (Roy Smith):
> dmc@videovax.Tek.COM (Donald M. Craig) writes:
>> I am looking for feedback on the quality and reliability of
>> the slide latch mechanism used on the DB-15 ethernet connectors.
> 
> 	In a nutshell, they suck!  There is no doubt that the single most
> common cause of problems in our entire network is loose ethernet tranciever
> cables, particularly on the backs of Sun's which provide no mechanical
> support for the cable at all.

I agree entirely with the above comment. These bent bits of tin, laughingly
described as retaining clips, are completely useless. They may work reasonably
well with light, flexible cables but they certainly do nothing when used with
the heavy, stiff transceiver drop cables.

>> "I am the Component Engineer for connectors at Sun.  In regards to your
>> question concerning the Ethernet DB-15 [...]  I am not aware of any
>> significant problems with mechanical integrity of the lock, or for that
>> matter with the connector in any aspect.
> 
> 	I'm not given to public flamage, but this guy must have his head
> firmly wedged in a dark place.  If he's not aware of any problems, it because
> he hasn't been listening.  I've complained loudly about this on the net
> before.  I've complained to Sun field service.  I've complained to Sun tech
> support.  Clearly those complaints havn't gotten back to the right people.
> 
> 	The stupid little stamped sheet metal clips are simply not strong
> enough to secure a connector with a big fat, heavy, and fairly stiff
> tranciever cable on it.  As long as the cable is secured so if can't move if
> accidentally moved, it's OK.  For example, on the tranciever ends, we lash
> the cable to the main ethernet trunk cable with 2 (or sometimes 3) wire ties
> a few inches away.  But on systems which might move a little (like a deskside
> Sun on wheels), or in situations where the cable might be disturbed (like
> hanging off the back of a desk) forget it.
> 
> 	What was wrong with good-old RS-232-style screws?  Or, if they really
> wanted a tool-less installation, why not Macintosh-style knurled screws, or
> maybe even centronics-style wire bails?

Does this guy never talk to field service people. We have complained bitterly
to several field service engineers over the years. Hoods for this type of
connector with knurled finger screws are readily available.
I should add that Sun are not the only workstation supplier using this useless
bit of bent tin as tranceiver drop cable retaining clamps.

> 	I really don't know what the DIX guys had in mind when they designed
> this connector.  Administering a network is hard enough without having to
> worry about which $5 connector is falling out.
> -- 
> Roy Smith, System Administrator
> Public Health Research Institute
> 455 First Avenue, New York, NY 10016
> {allegra,philabs,cmcl2,rutgers}!phri!roy -or- phri!roy@uunet.uu.net