2 Ethernet cabling question

[Joe Zeff]

On 12/25/2010 12:32 PM, Mikkel wrote:
> If you look at the cable, you will see that the wires are twisted in
> pairs. White-orange with orange, white-blue with blue, etc. For
> noise cancellation, it is important that you use pairs for each data
> path. On a short cable, you can get away with out doing this, but it
> is not a good idea. Each pair also has a different twist ratio -
> twists/inch. This helps prevent them from interfering with each other.

This is a tad off-topic, but I think some of you might find it 
interesting.  My apologies to those who don't.

Several years ago, I was doing phone tech support for a company.  One of 
our clients was having trouble with a piece of equipment connected by a 
run of Cat-5 through a pipe.  Part of the trouble-shooting was making 
sure there weren't any cabling issues, so the client brought out an 
electrician.  Not only weren't the colors on the cable standard, they 
were different at each end!  Our only guess was that there was a splice 
down in the pipe because whoever'd run the cable had run out of one 
batch and simply spliced on another.  I told the electrician that he'd 
have to do continuity tests from one end to the other to match up the 
colors, and he asked me how to do it.  I had him put the client on and 
told him to get in an electrician who knew how to do his job.  Yes, my 
boss would have backed me up if there'd been a complaint because that's 
part of what an electrician is supposed to know.