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Bad crossover cable?

 
 
Dmitry
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      11-04-2003
Hi,

I recently found an improperly wired crossover cable between two of my
switches as shown below.
Pin1 <---> Pin6
Pin2 <---> Pin3

So in essence, I have a reversed polarity between send and receive.
TX+ <-----> RX-
TX- <-----> RX+

The network still functions but with interrmitent connectivity
problems.

Anyone know what the actual effect is of crossing pin 1 with pin 6 and
pin 2 with pin 3 on a 100BaseT network?

I am also wondering how it worked at all.

Thanks in advance
 
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D. Abaimov
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Posts: n/a
 
      11-04-2003
Both networked devices have operational amps/comparators that only pick up
the voltage difference between the two conductors. It's called "balanced
signal" Therefore, it does not really matter what polarity it is. Well, this
is in theory. In reality though, the actual transmit/receive circuitry is
pretty complex, and in some cases it may be sensitive to noises that could
have been filtered out if the polarity was right.
--
Dmitri Abaimov
http://www.cabling-design.com
Residential Cabling Guide and other useful online resources for premises
wiring users and professionals
http://www.cabling-design.com/resour...sidential.html
Residential Cabling Guide 2003

"Dmitry" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> Hi,
>
> I recently found an improperly wired crossover cable between two of my
> switches as shown below.
> Pin1 <---> Pin6
> Pin2 <---> Pin3
>
> So in essence, I have a reversed polarity between send and receive.
> TX+ <-----> RX-
> TX- <-----> RX+
>
> The network still functions but with interrmitent connectivity
> problems.
>
> Anyone know what the actual effect is of crossing pin 1 with pin 6 and
> pin 2 with pin 3 on a 100BaseT network?
>
> I am also wondering how it worked at all.
>
> Thanks in advance



 
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