rj-45 connector

[Ian Moore]

On Sun, 28 Nov 2004 20:25, johne edw wrote:
> dear sir,
> i've 3 computers and  i want to connect  them togather as a workgroup
> network via a hub. i know that the both ends of cable must have the same
> sequense of color .please advice me if that the color sequence of wires
> connected to rj-45 connector is important or not?..i mean, in another word,
> is there a special sequense of color ? or any sequense of color will be
> valid when the both ends have the same color sequense ? i wish that
> response will come on soon........best regards
>
This is rather OT, but...
Yes, the order is important, the cable will probably work at low speeds over 
short distances as long as both ends are the same, but will be unreliable at 
high speeds or longer distances unless you follow the correct order.

Basically there are 2 standards, EIA/TIA-568A and EIA/TIA-568B.
In Australia & probably in Europe I suspect, the preferred standard is the A 
standard. I think the US might use the B standard?

EIA/TIA-568A standard:
1 Green/White
2 Green
3 Orange/White
4 Blue
5 Blue/White
6 Orange
7 Brown/White
8 Brown

(see diagram below for pin numbers)
NB, the Blue pair is reversed - that's not a typo!
Both ends are wired up the same way, BUT, if you want to connect 2 network 
cards directly together without a hub, you would need to use a crossover 
cable which looks like the above on one end, but the other end is wired like 
this:

1 Orange/White
2 Orange
3 Green/White
4 Blue
5 Blue/White
6 Green
7 Brown/White
8 Brown

Pin numbers are like this (looking at the connector with the tab underneath 
and the cable coming from the left)

                   |---------------------------|
                   |                      ---- | 1
                   |                      ---- | 2
-------------------|                      ---- | 3
                   |                      ---- | 4
                   |                      ---- | 5
-------------------|                      ---- | 6
                   |                      ---- | 7
                   |                      ---- | 8
                   |---------------------------|

Hope that makes sense.

Cheers,
-- 
Ian

GPG Key: http://homepages.picknowl.com.au/imoore/imoore.asc
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