[comp.dcom.lans] Special reward for Ethernet xceiver cable designer

mo@seismo.UUCP (08/31/87)

I suspect that many of you out there share my belief that
if there is in fact any justice in this world, there is
a special place in Hell reserved for the person who
design the bloody clip which is claimed to hold a
transciever cable in place at either end.

This is certainly one of the worst industrial designs
ever conceived and sets some kind of new record
for the damage done by standards committees.

So, with my speen appropriately vented, does anyone
out there have any good suggestions for dealing with
these rotten blighters??  I have considered SuperGlue,
but we reconfigure hardware too often.  I really wish 
Apple's D-connectors with the long Jackscrews had
come along, but alas, I guess we are stuck with the
current state of affairs.

How do you tell a customer they should simply expect
to have to screw with the cables on a regular basis??
"Just wiggle it until 'ie0: No Carrier' stops coming out."

What do other people do??

	-Mike O'Dell

wunder@hpcea.CE.HP.COM (Walter Underwood) (09/01/87)

> [fully justified tirade about silly clips on transceiver cables deleted]
>
> What do other people do??
>
>	-Mike O'Dell

We use Cheapernet, or ThinLAN, or whatever you want to call it.  BNC
is a great design, as long as the crimp is done right.  Otherwise, the
coax can pull out of the connector.

Real transceiver cables only go in computer rooms, where we can properly
strain-relieve them.

wunder

montnaro@sprite.UUCP (09/01/87)

In article <44078@beno.seismo.CSS.GOV> mo@seismo.CSS.GOV (Mike O'Dell) writes:
>I suspect that many of you out there share my belief that
>if there is in fact any justice in this world, there is
>a special place in Hell reserved for the person who
>design the bloody clip which is claimed to hold a
>transciever cable in place at either end.

Hear! Hear!

>This is certainly one of the worst industrial designs
>ever conceived and sets some kind of new record
>for the damage done by standards committees.

Agreed.

>So, with my speen appropriately vented, does anyone
>out there have any good suggestions for dealing with
>these rotten blighters??
>What do other people do??
>
>	-Mike O'Dell

We replace all of the connector hoods with screw down posts, as in
most metal RS-232 hoods I've seen. We now install all wall taps this
way and with only a few exceptions, all connectors on machines are
converted.

If you are determined to use a slide connector of some sort, there is
one that slides the other way (how should I say this?):

	------------------	^
	\ . . . . . . . . /	| this way, not <--> that way.
	 \ . . . . . . ./	v
	  -------------

For some reason, that style of slide connectors seems to lock better.
Look in an AMP catalog. The connectors with 90 degree bends are
constrained to use that kind of connector. 


Skip (montanaro@ge-crd.arpa or uunet!steinmetz!desdemona!montanaro)

dal@gcm.UUCP (09/01/87)

> I suspect that many of you out there share my belief that
> if there is in fact any justice in this world, there is
> a special place in Hell reserved for the person who
> design the bloody clip which is claimed to hold a
> transciever cable in place at either end.

I couldn't fail to disagree less with this statement.  I have had more
trouble with those slide-clips than I'd care to mention.  In a
multi-vendor environment, it's amazing to see how many variations on a
"standard" there can be.  Add to that the fact that even with the best
fit, the cable can be pulled out without much trouble.

I have found two solutions that seem to work.  The first thing to try
is to reduce the height of the shoulder on the studs of the male
connector.  Some of these are shimmed with washers that can be removed
allowing the cable to be inserted further, making a better connection
and allowing the slide-clip to hold better.  Adjusting the prongs on
the slide-clip also helps.

Sometimes, however, this can't be done:  either the shoulder is too
high (e.g., AMP hood), or, with the new (read: cheaper) type where the
stud is screwed into a tapped hole in the hood (e.g., Cabletron) and
the stud has a wider, unthreaded section that prevents it from being
screwed all the way in.

If that fails or is impossible, I have found that retrofitting good old
RS-232-style screws works quite well.  You have to remove the
slide-clip (you can put it on the floor and stomp on it if you want)
and replace it with "female mounting hardware" (those little
socket-like things that you screw the screws into).  You also have to
remove the studs and replace them with screws ("male mounting hardware"
-- we can't be sexist; this is USENET!).  In the case of the hoods with
tapped holes, the entire hood must be replaced (I use AMP 745172-1).
This method works great with Suns.  These parts can usually be taken
from old RS-232 cables.  After all, who uses ordinary terminals any
more? :-)

Dan
seismo!philabs!gcm!dal

jhc@mtune.UUCP (09/01/87)

In article <44078@beno.seismo.CSS.GOV> mo@seismo.CSS.GOV (Mike O'Dell) writes:
>I suspect that many of you out there share my belief that if there is in fact
>any justice in this world, there is a special place in Hell reserved for the
>person who designed the bloody clip which is claimed to hold a transciever
>cable in place at either end.

I will second, third and fourth this motion.

>So, with my speen appropriately vented, does anyone out there have any good
>suggestions for dealing with these rotten blighters?? 

Personally, I bend the clips by hand, using a pair of long-nose pliers,
until I can only just force the clip across and into place as it is so
tight, then I use yards of black sticky electricians tape and/or cable
ties. And lots of strain relief.
-- 
Jonathan Clark
[NAC,attmail]!mtune!jhc

An Englishman never enjoys himself except for some noble purpose.

geoffb@trwind.TRW.COM (G. Geoffrey Baehr) (09/01/87)

In article <44078@beno.seismo.CSS.GOV> mo@seismo.CSS.GOV (Mike O'Dell) writes:
>I suspect that many of you out there share my belief that
>if there is in fact any justice in this world, there is
>a special place in Hell reserved for the person who
>design the bloody clip which is claimed to hold a
>transciever cable in place at either end.
>
>What do other people do??
>
>	-Mike O'Dell

Well, we make an 'L' shaped bracket, which we screw into
the holes for the clip, then wire tie the cable to the clip.
This seems to work well, as the clip is 16ga aluminum.

It looks like this:

  ||---------- <-clip
  |
  || <- xcvr cable plug
  |


Hope this helps. Now, what REALLY is interesting is how people
propose to hold the direct xcvr cable receptacle to transceiver
body units (such as DESTA's ) on with ...




-- 
Geoffrey Baehr
TRW Information Networks Division 23800 Hawthorne Blvd, Torrance CA 90505
ATT: 1 213.373.9161 (+10db Noise/Signal Ratio Usually) 
ARPA: geoffb@trwind.TRW.COM  USENET: ..trwrb!trwind!geoffb

jerry@oliveb.UUCP (09/02/87)

In article <44078@beno.seismo.CSS.GOV> mo@seismo.CSS.GOV (Mike O'Dell) writes:
>I suspect that many of you out there share my belief that
>if there is in fact any justice in this world, there is
>a special place in Hell reserved for the person who
>design the bloody clip which is claimed to hold a
>transciever cable in place at either end.
       ^^ i before e except after c

Actually the designer may be less at fault than the manufacturer.  At on
of my first jobs they used "slide-locks" for the 25 Pin RS232
connections.  It was great being able to swap terminals without fooling
with a screwdriver.  We had no problems that I can recall.  (Actually
figuring out which direction locked was a pain.)

The slide-locks on transceiver cables, on the other hand, aren't worth
!{}!*.  Particularly bad are the type that are in two pieces, that is a
separate unit on each end of the connector.  The one piece units are a
little stiffer but still seem to suffer from crummy metal.  There
doesn't seem to be any consistancy about which way they lock.  Some
slide up and some down.  I usually swap them around to be the same.

The best suggestion seems to be to strain relief the cable.  (This kind
of defeats the "easy connect" feature.)  Installers recommend
tie-wrapping the transceiver cable to the ethernet cable near the
transceiver tap.  This works best if the transceiver has its connection
adjacent to the side with the tap so both cables run parallel.  On the
equipment end secure the cable within a few inches of the connection.
If you use two cables in series then you are asking for trouble.

3Com doesn't use the slide-locks on their PC card.  They have a little
bracket that fits over the connector and clamps it to the back panel
with screws.  I guess someone there must share your views.  Cabletron
has a bracket that fits on the back of their multi-port-repeater (like a
DEC DELNI).  It provides strain relief for all 9 transceiver cables and
the power cord.
				Jerry Aguirre

eshop@saturn.UUCP (09/02/87)

Should the screws be English or metric?  This problem faced
the IEEE488 GPIB standard.  Hewlett Packard originally used
English and when the standard came out, sent out replacement
metric screws to all who requested them.

The IEEE 802.3 standard is very clear that the flange of the
15-pin D-connector is to be mounted on the outside of the 
case.  If, like Sun, you mount it on the inside of the case,
the slide lock mechanism is at the wrong height relative to
the connector flange to work with standard cables.  Sun
provides mating transciever cables that have the height of
the posts adjusted so that the connector mates properly.  So
much for plug compatibility :-)   On most transciever cables
there are two washers under the lock posts.  Both washers are
supposed to be there for standard cables.  You can get the
connectors to mate more snugly by removing one or both washers.

We find that we have to replace about two slide lock clips that
are bent beyond all hope.  We don't find that a major hassle.
A feature of the slide lock system that we really like is that
right angle hoods are available.  We use these on cables that
attach to wall plates so the cable can exit the wall and drop
down close to it.  

smith@COS.COM (Steve Smith) (09/02/87)

In article <44078@beno.seismo.CSS.GOV> mo@seismo.CSS.GOV (Mike O'Dell) writes:

>I suspect that many of you out there share my belief that
>if there is in fact any justice in this world, there is
>a special place in Hell reserved for the person who
>design the bloody clip which is claimed to hold a
>transciever cable in place at either end.

>This is certainly one of the worst industrial designs
>ever conceived and sets some kind of new record
>for the damage done by standards committees.

>So, with my speen appropriately vented, does anyone
>out there have any good suggestions for dealing with
>these rotten blighters??

For the tranciever end, the most common solution is a couple of big
tiewraps going around the tranceiver, and, possibly, around the tap as
well.  They should cross in the middle of the tranceiver.

For the other end, I haven't a clue.  Let me know when you find a way!
Occasionally, you can find enough room to sneak a tiewrap through (like
on a VME bus board) but not often enough.  Usually, all you can see is a
blank panel with a connector in the middle of it.

A member of the IEEE 802.3 committee has told me that he considers that
connector to be the biggest mistake they've ever made.

-- 
                           __
 -- Steve          /      /  \      /         "Truth is stranger than
S. G. Smith      I \ O    |  _    O \ I        fiction because fiction
smith@cos.com      /      \__/      /          has to make sense."

bc@halley.UUCP (Bill Crews) (09/04/87)

In article <4333@oliveb.UUCP> jerry@oliveb.UUCP (Jerry F Aguirre) writes:
>In article <44078@beno.seismo.CSS.GOV> mo@seismo.CSS.GOV (Mike O'Dell) writes:
>>transciever cable in place at either end.
>       ^^ i before e except after c

>doesn't seem to be any consistancy about which way they lock.  Some
                               ^ a instead of e when it belongs there

>				Jerry Aguirre

I recommend against spelling corrections in technical groups.  I did that a
couple of years ago with very unproductive results.

-bc
-- 
Bill Crews                                   Tandem Computers
                                             Austin, Texas
..!seismo!ut-sally!im4u!esc-bb!halley!bc     (512) 244-8350

stpeters@dawn.steinmetz (09/19/87)

What we do here is replace the posts that the clips slip onto with
screw-on posts.  We then use mating connectors on our tranceiver
cables that screw on much the way a normal RS232 connector screws on.
This has solved all our problems with the clips.

Replacing the posts takes only seconds.  I do not know where the elves
in charge of our Ethernet get the cable connectors and conversion
kits, but they obvious buy them from some enterprising connector
supplier.

If you can't find this hardware, mail me a request, and I'll ask our
elves.  If I get a lot of requests, I'll post the source to the net.

Dick St.Peters                        
GE Corporate R&D, Schenectady, NY
stpeters@ge-crd.arpa              
uunet!steinmetz!stpeters
Dick St.Peters                        
GE Corporate R&D, Schenectady, NY
stpeters@ge-crd.arpa              
uunet!steinmetz!stpeters