RE: Networking problems.

["K. C. Li" <li@xxxxxxxxx>]

On Wed, 12 May 2004, Paul Gale wrote:

> If that all fails - how about hiring one of those advanced cable
> testers - i.e. Fluke meter?

We had a problem with one long run of Ethernet cable in that it would only
work at speed of up to 10Mb/s, even though the cable itself is capable of
operating at 350Mb/s and the switch equipment is rated at 100Mb/s.
Thinking that it might be because of a break in one of the wires or the
curvature of some of the bends were too severe, the cable was replaced
three times but the problem persisted. A Mills C00-1605 Remote Cable
Tester with lots of flashing lights and a buzzer didn't find any problem
with any of the cables.

Eventually, the problem was traced to how the wire pairs were wired to the
wall socket and RJ45 plug. The wiring is not a "logical"
sequential colour
pairs at both ends but one pair (orange) has to straddle across another
pair (blue). The problem was completely solved by wiring in the following
way:

Pin Colour

1   Green/white
2   Gree
3   Orange/white
4   Blue
5   Blue/white
6   Orange
7   Brown/white
8   Brown

It might not be the conventional way of pairing the colours to the pins
but providing both ends are done in the same way, it should be fine.

Regards,

Kwong Li
li@xxxxxxx
Laser Business Systems Ltd.
http://www.laser.com
http://www.cbus-shop.com