[CentOS] 2 Ethernet cabling question

Blake Hudson blake at ispn.net
Wed Dec 29 14:52:49 UTC 2010


-------- Original Message  --------
Subject: Re: [CentOS] 2 Ethernet cabling question
From: Raymond Lillard <ryl at sonic.net>
To: CentOS mailing list <centos at centos.org>
Date: Wednesday, December 29, 2010 12:36:43 AM
> On 12/28/2010 08:01 PM, Drew wrote:
>>> The colors do not matter.  What matters is the pairs.
>> And every person who comes after you will curse your work because
>> *both* the colors *and* the pairs are part of the 568A/B standard.
>>
>> In my shop if you tried that you'd be very quickly looking for work
>> elsewhere. ;-)
> Electrically it matters also.  If you want to be able to
> have the cable usable to the full distance specified by the
> standard, colors matter.  The reason is placement in the
> bundle and crosstalk between the pairs.
>

I concur. What some people gloss over is that not all the pairs are the
same. Take an ethernet cable apart at some length greater than a few
inches and you will immediately see that some pairs can have twice as
many twists as another. This results in slightly different electrical
and delay properties for each pair - that become exaggerated at
distance.  Bottom line, stick with the color scheme.



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