Re: Network Cabling

[Tim Gimmel <tim@gimmel.org>]

Yep, thars meaning in the madness.  It comes from the telephone Industy.  In a 25 pair cable there
are 5 groups of 5 colors: blue, orange, green, brown, slate, and 5 'tracer' colors: white, red,
black, yellow and violet.  white/blue is the first wire which is tip and blue/white is ring, w/o is
tip, o/w is ring.  This pattern repeats through all the colors.  Then if you have 100 pairs in a
cable, each group of 25 will have 2 ribbons, a white/blue ribbon and a white/orange ribbon.  This
repeats with all the groups of 25 pair bundles.

So.  In your average eth cable there are 4 pairs, w/b b/w, w/o o/w, w/g g/w, w/b b/w. If you look
at your cat5 cable thats the colors in the cable.  Now..

pins 1 and 2 white blue PAIR
Pins 3 and 6 white green PAIR
pins 4 and 5 white orange PAIR
pins 7 and 8 white brown PAIR

(In ethernet pins 1,2 and 3,6 are the trasmits and receives, I can't remember which is which)
This is a 'straight' cable, PC to Hub, but for a cable going from hub to hub you need to reverse
the w/b pair and the w/g pair on ONE end, this is a crossover cable.

The key to all this is the word "PAIR".  If you just randomly pick wires you might split pairs. 
This isn't a problem is the cable is only a couple of feet long.  But if its 200 ft long and
running 100mb you can forget it!  You need the balance of twisted pairs.

Sorry for the long winded answer.

Tim


KoReE <koree@ameth.org> wrote:
> I've never really used any standard cabling color coding.  I've been
> curious if there is a standard of some sort for this.  For example if a
> crossover patch cable has a certain standardized color, etc.  This may
> sound lame, but I'm just deciding if I'm going to use such a system.  Up
> until now, I've used gray cable and labels because they actually say what
> the cable is and how it's wired :D
> 
> Koree
> 
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> Koree A. Smith  | Co-Administrator, ameth.org
> koree@Ameth.org | http://www.koree.net/
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