[Gllug] Electrical interferense?

[Chris Bell]

On Mon 22 Nov, Rich Walker wrote:
> 
> "Henrik Morsing" <henrik at morsing.cc> writes:
> 
> > Hello guys,
> > I've just moved house and have some unexplainable problems.
> >
> > 1. My main (8 year old PII) computer has slowed down about 50 times. It
> > now takes 1:40 to boot up. I tried reinstalling it but even the
> > installation process is extremely slow. There's nothing in the logs, no
> > errors, no cpu usage and no I/O wait. It seems as if the CPUs themselves
> > have just slowed down!
> 
> I have seen this with machines occasionally. 
> 
> You *are* using STP rather than UTP for your network cables?
> 
   I have not seen any problem associated with mains supply feeder
interference using UTP cables UNLESS the connections are incorrectly wired,
but I HAVE seen problems when someone connected random wires to random pins
rather than using the correct wiring, the pairs are NOT connected as you
would expect from a quick look at the connectors. Most testers will show a
cable with the correct pins connected using the wrong wires as still OK, you
need to get out your magnifying glass.

Standard ethernet connections 1 to 1    Cross wired cables are connected
         ___________________ 
         |                 |
W/O  ----|                -| 1          1  W/O  3  (W/G)
O/W  ----|Cable  Contacts -| 2          2  O/W  6  (G/W)
W/Gn  ---|............... -| 3          3  W/G  1  (W/O)
Bu/W  ---|              . -| 4          6  G/W  2  (O/W)
W/Bu  ---|............... -| 5
Gn/W  ---|                -| 6
W/Bn  ---|(Latch below)   -| 7
Bn/W  ---|                -| 8
         |_________________|

Pairs DO cross over in the middle!
 The only pins normally used are 1, 2, 3, 6

-- 
Chris Bell

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