[Tfug] Yet another poser

[Bexley Hall]

OK, this is one of those philosophical questions
that you either can't get *wrong* -- or, you can't
get *right*!  :-/

I am a big fan of "standardized" cables.  Having
spent a few years designing communications gear,
I quickly learned that keeping track of 4,928
different versions of a "25 pin serial cable"
was just *not* how I wanted to spend my career!

And, looking through a box of 4,927 of those
cables in the hope of finding the 4,928th
variety to save myself the trouble of having to
build one from scratch ranks right up there with
waiting for a dentist on a holiday weekend to
take care of an abcessed tooth!  :-(

So, in as much as is possible, I have tried to
rid myself of this problem by "picking" what I
think is an appropriate "standard" cable and
then building "widgets" to append to said
cable to modify it's *overall* character.

E.g., I have lots of M-F 25 pin "straight through"
cables that I use for most serial and "parallel"
cables.  My little box of widgets, for example,
contains a device with two male connectors on it
labeled "female gender swap" (i.e., it converts
a female connector that it *mates* with into a
*male* connector, effectively).  So, put one
of these on a generic M-F cable and you end up 
with a M-M cable.  Likewise, put a "male gender
swap" widget on the same generic cable and it
becomes a F-F cable.

Of course, the more *interesting* widgets are
those that actually alter the effective wiring 
of the cable -- not just the gender of the 
connectors on its ends.  For example, one widget
is a "null modem" which, of course, converts
the generic cable into a "null modem cable".
Another widget swaps the "port A" and "port B"
connections on some older SPARC machines.  Still
another converts the generic cable into one
suitable for use as a "PLIP" cable.  :>

<shrug>  YMMV.  This works *great* for me!
(Note that I can get cables of arbitrary lengths
just by cascading generic M-F cables onto the
"widgetized" cable!  :> )  *Technically*, these
"widgetized cables" aren't identical to "real"
cables -- except at DC.  But, they are usually
only "temporary use" so the differences never
really amount to any *noticeable* performance
hits, etc.

Anyway, I wanted to do the same thing with
network cables.  To that end, I have some little
widgets with a pair of RJ45 connectors back-to-back
(the key thing about widgets is they are *small*
so you can store 50 different varieties in a 
shoebox -- try doing that with 50 different
varieties of *cables*!).  They are wired
"straight through".  As such, their only real
use is as "cable extenders" -- i.e. plug two
RJ45 cables into it and you end up with a cable
that is as long as their combined lengths.

It's a cakewalk to turn one of these "RJ45 widgets"
into a "crossover" widget.  I.e. swap pins 1&3
and 2&6, then glue the thing back together.

The question becomes what to do with the other
4 conductors in the "widget".  I suppose to
truly mimic a crossover cable, they should be
present and run "straight through" -- is this,
in fact, how "real" crossover cables are wired?
Or, do vendors skimp and simply *omit* these
extra conductors to save a few millipennies?

Lastly, how are crossover cables typically
identified?  I had assumed I would just slap a
label on this (I label all of my widgets since
you "can't tell the players without a program"!)
saying "CROSSOVER"...?

(Yeah, I think WAY too much about these little
details... :>  )

Thx!


      ____________________________________________________________________________________
Don't let your dream ride pass you by. Make it a reality with Yahoo! Autos.
http://autos.yahoo.com/index.html