[Robotgroup] A Twisty Question -- re: Cat-5 Cable

[Paul Atkinson]

Tom,

Have you got any pictures or links to that pcb routing method? I've seen
lots of interesting pcb effects, but don't recall seeing that one yet.

Paul

On Thu, Jun 19, 2008 at 8:45 PM, TomD <TomD at hyperweb.com> wrote:

> Vern Graner wrote:
>
>> Andre Lamothe wrote:
>>
>>> but under the specs it is supposed to.
>>>
>>
>> And there's the rub.. I can't find a "spec" that tells me which pair(s) if
>> any have more or less twists... :(
>>
>> Vern
>>
>>  Well, they may vary the number of twists/ft over a given length of wire
> so on average they have the same number, but it's always varying slightly
> within the impedance spec +/- number. That way no one pair is faster or
> slower
> over a long run of cable.
>
> Interestingly, something similar is done in modern PC boards, they don't
> run the
> traces straight anymore, they zig-zag slightly so the underlying fiberglass
> weave doesn't
> affect a long trace running over it, changing the impedance with respect to
> a neighboring
> that runs over epoxy.
>
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