Re: Problem: UTP only works at 10 MHz

Claudio Bogado Pompa <peloto@xxxxxxxxx> wrote in part:
I used same order of colors in both ends, brown, white
and brown, green, white and green, blue, white and blue,
orange and white and orange.

All pairs side-by-side. While intuitive, this is incorrect
for 10/100baseTX because it splits a pair. T-568-B is:

(viewed tab down, cable from right)
8 - brown
7 - wh/br
6 - green
5 - wh/blue !
4 - blue
3 - wh/green !
2 - orange
1 - wh/or

Note the blue pair is perfectly in the middle and the green
pair straddles it. You can swap colors if you like and it
will still work. But you cannot move pairing positions.
Ethernet relies on pins 1&2 to be on a single pair and pins
3&6 to be on another for noise cancellation.

This counter-intuitive standard evolved for phone compatibility.

-- Robert


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