On 2016-11-14, Michael A. Terrell wrote:
DoN. Nichols wrote:

Well ... 25-pair cables *are* 50 wires, and the dots on solid
uniquely marked each wire in that count. (Aside from that, the two wires
in a pair were also twisted -- to minimize crosstalk to adjacent pairs.)
The twisting helps keep them together so you don't have to search
through 49 other wires to find the other half of a pair. :-)


Not only re he pairs twisted, but the twist rate varies from pair to
pair to reduce the crosstalk even further.

Certainly in the 4-pair cables (Cat-5 and better) used for
10Base-T/100Base-T/1000BaseT ethernet jumpers. :-)

One thing which is rather weird -- as they are crimped into
RJ-45 connectors, at least -- is that for some reason or other, the
primary and secondary wire colors are interchanged for the first pair
only (pins 4 & 5 -- in the center of the connector). I can't even
figure out how it could make a difference -- as long as both ends are
done the same. :-)

Enjoy,
DoN.

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