UTP cat5 or 6

Kiwi

hello,

I have noticed the following thing.

In a utp cat5 or Cat 6 cable there are different pair of cable, each with colors. (blue,brown,orange,green).

All of these pairs are twisted, wright?

So why is it that the brown pair is less twissed then the green, blue or orange cable?

Does somebody knows that?

Kurt

Bruce Bates

Kurt -

I'm not sure how you came to that conclusion, and suspect what you say may be true for the one piece of cable you looked at. In general, that isn't usually the case.

Generally, cable intended for telephony or communications use often has, and should have, what's known as "random lay" twists in it. What this means is that there is no particular pattern to the number of twists in a given section BUT that over the course of (say) one or two meters of cable there will be a guaranted number of twists. If the twists were symmetrical, that wouldn't help nearly as much in avoiding cross-talk and other forms of internal interference. There is also less of a chance of any inductive coupling with asymmetrical twisting.

If you were to strip a different section of cable you might well find some other pair that seems to appear with fewer twists, as the brown pair did.

Regards,

Bruce Bates

Post Edited (Bruce Bates) : 9/26/2006 9:56:48 AM GMT

Robert Kubichek

Kiwi said...
hello,

I have noticed the following thing.

In a utp cat5 or Cat 6 cable there are different pair of cable, each with colors. (blue,brown,orange,green).

All of these pairs are twisted, wright?

So why is it that the brown pair is less twissed then the green, blue or orange cable?

Does somebody knows that?

Kurt

Here is from Wiki,

"Cat 5 cable typically had three twists per inch of each twisted pair of 24 gauge copper wires within the cable."

Here is further info,

en.wikipedia.org/wiki/TIA/EIA-568-B

and,

en.wikipedia.org/wiki/Twisted_pair

Usually the twists per pair are the same for length.


Bob