LAN Cable Colour Coding

[pakigang]

YO!

Just got a question about this lan cable colour coding. Normally the standard color coding is

white orange
orange
white green
blue
white blue
green
white brown
brown

if you google about these standard there are sites saying colour has nothing to do with networking i.e. it a standard but not necessary to follow as long as it remains parallel.

My experience while cabling is if i don't use the same colour coding there is a speed difference. Now i don't know if my experience is right or these sites. I don't remember the brand of the cable but it was cat5e. One of my friend also said that there is some resistance or something difference in each pair.

Can anyone elaborate on this. Thanks for your time.

 

[JackMDS]

These pages has some pointers and links with colored pictures answers.

Link to: Wiring - I would like to wire my Networked Computers (Home Wiring).

Link to: Using CAT5 for Telephone Lines, and other Media.

:sun:

 

[ScottMac]

Pair ordering is extremely important, especially in Cat 5 and below.

The most common mistake, and one of the most detremental (from a speed /efficiency standpoint) is when the cables are wired <pair><pair><pair><pair> - regardless of the color order or the length, this cable will never perform anywhere near the rated speed .... here's why:

Ethernet uses conductors 1&amp;2 and 3&amp;6 (gig also uses 4&amp;5 and 7&amp;8). If you cont across, you'll see that pin three is on one color pair, and pin six is on another. This is called a "Split Pair" and, because the two colors are not properly twisted together, the crosstalk (near-end -NeXT or Far-end-FeXT) on this cable will be astronomical ... killing any chance for any kind of performance.

In fact, the "hallmark symptom" for a split pair 3/6 is that the network works (but probably at reduced performance) at 10Meg, but doesn't work (or works really bad) at 100 and/or full duplex.

Second point: Even if you order the pair such that there is no split at 3/6, but the colors aren't according to one of the two acceptable specifications, the cable is likely to still perform below par. The specification exists so that manufacturers of cabling products can optimize the media for the intended function ... structured cabling is designed for more than just data cabling.

Since the manufacturer knows that (likely) Ethernet traffic will be put on 1&amp;2 and 3&amp;6, the color pairs for those conductors (orange and green) are optimized to handle the frequency and pulse density that is likely to occur with Ethernet. If you were to use the other colors (blue and brown), chances are that they are not fully optimized for Ethernet....especially at Cat 5 and below.

Final point: It take no additional effort to properly order the conductors. You'd have to be (one of) the biggest (and laziest) idiots in the world to NOT use the spec. For those people, it is my hope that the mechanic that works on their car has the same attitude about following a recommendation or specification when fixing the idiot's car.

I know it sounds extreme, but I've personally spent many hours chasing down problems created by these miserable, lazy, stupid a$$holes and their cavalier ignorance. A quick death is way too good for them. They should be forced to eat liver and broccholi for the rest of their lazy-assed lives. They should have to ... well, never mind.

The spec is there to make everyone's life better and easier. It increases the likelyhood of the network to work at best efficiency. The next time someone suggests not following the spec, just point &amp; giggle at 'em, call 'em names, laugh in their face .... and maybe buy 'em a steaming plate of liver &amp; broccoli for me.

.02 / FWIW

Scott

 

[JeffMD]

I dont get it, why wouldnt you properly color match? And why would some cables differ from other. optimised for ethernet, what ELSE uses cat5?

 

[cmetz]

JeffMD, older cables had better quality pairs for orange and green, for enhanced Ethernet performance, and just-to-spec for the other two. For example, my Belden DataTwist 350 seems to have double the twists per unit length on those pairs. This behavior was fine and dandy until 1000BaseT came along, which needs as much performance as it can get on all the pairs, and so you're down to effectively the lower performance level of those other two pairs.

Color matching has nothing to do with pin matching here. It's just that the old telco standards used as the basis for EIA-568A&amp;B chose to pair up 1&amp;2 and 3&amp;6 and that's how 10BaseT did it. If we were designing this all today from scratch, we'd probably use 1&amp;2 and 3&amp;4, it'd be much simpler, but that's not the standard. So you either follow the standard or you don't, and one of those two choices is going to give you the performance the standard says you should, and one of you gives you a cable not up to spec.

T1 circuits use twisted pair and connectors that are physically the same as an RJ45, but the pair to pin mappings are different than EIA-568A&amp;B. People often use Ethernet patch cables to connect T1s for short distances and then spend a LOT of time confused when it doesn't work for long distances. Same problem. Spec says that you use certain pairs to get the delivered signal performance, and if you don't do that way, you're not up to spec and then don't be surprised if it doesn't work right.

 

[ScottMac]

Some of the other uses &amp; pin-pairs:

T1: 1&amp;2, 4&amp;5 (although spec for T1 is "premises cable" individual shielded pair in a shielded sheath)
56KDDS: 1&amp;2, 7&amp;8
ATM: 1&amp;2, 7&amp;8
Video (Baseband - the yellow RCA): most often 7&amp;8 or 3&amp;6
Audio (baseband): 1&amp;2, 3&amp;6
Video (S-Vid) - 3&amp;6, 4&amp;5
Serial: 1-8
Phone: (line1) 4&amp;5, (line2) 3&amp;6, (line3) 1&amp;2, (line4)7&amp;8
Video (RF) 4&amp;5 (and possible also 3&amp;6, depending on the BALUN)
3270 (mainframe terminal): 4&amp;5
5250 (s34, s36, s38, AS400 terminal): 4&amp;5 or 3&amp;6
Token Ring 3&amp;6, 4&amp;5

Other utility (i.e., alarm circuits)

The whole idea of structured cabling was to get rid of all of the proprietary cabling that was in-use in the early eighties: to be able to use one cable plant to carry signaling from nearly any kind of device.

Ethernet data is / was only a small part of it.

FWIW

Scott

 

[pakigang]

Thanks for your reply!

 

[Kelemvor]

AFAIK, Originally, the whole point of the standard 8 wire cable was because they had the great idea that one cable could do everything. Some wires for computer, soem for phone, some for fax, etc and then some sort of splitter on each end to separate them out. So they came up with the standard to ake everything work nice.

However that whole idea never really panned out which is why there's no the A and B standards.

 

[EULA]

Originally posted by: JeffMD
I dont get it, why wouldnt you properly color match? And why would some cables differ from other. optimised for ethernet, what ELSE uses cat5?

I run cat5 for my phone, and video signals.