[Gllug] OT: CAT ScTP cable.

[Chris Bell]

On Wed 01 May, Jim Cheetham wrote:

> Get an example of the pin connections from somewhere (disassemble a
> working cable, or go to the web). Decide on a colour combination that is
> actually in the cables you have, WRITE IT DOWN and NEVER VARY the
> pattern, after you get one working. Always be very careful to remember
> which way up you are counting (i.e. you define pin 1 as the left-most
> pin when the RJ45 spring-clip is facing down ... or anything that woprks
> for you). The secret is repeatability repeatability repeatability rather
> than conforming to someone else's system :-)
> 

   CAT5 cable is designed and manufactured to pass the high frequency data
with minimum pulse distortion, crosstalk, and interference. The correct
pairs should be used. The twist in each pair is different, and should be
continued right to the terminals. The provisional specification for CAT6
cable includes a cross-shaped spacer between the pairs to ensure they stay
apart.

   The outer needs to be cut back cleanly, far enough to be able to
separate then lay out the pairs. They should be trimmed to the correct
length so that all the wires reach the end of the plug with the outer well
under the clamp, but beware that the wires are difficult to insert correctly
before crimping.

Standard ethernet connections are 1 to 1
          _____________________
         |                     |
W/O -----|                    -| 1
O/W -----|Cable     Contacts  -| 2
W/Gn-----|..................  -| 3
Bu/W-----|                 .  -| 4
W/Bu-----|..................  -| 5
Gn/W-----|                    -| 6
W/Bn-----|    (Latch below)   -| 7
Bn/W-----|                    -| 8
         |_____________________|

Pairs DO cross over in the middle!





Cross wired cables for direct computer to computer links are connected

1  W/O   to  3
2  O/W   to  6
3  W/G   to  1
6  G/W   to  2

   Normally only 2 pairs are used, and I have been given conflicting
information about the other connections.


-- 
Chris Bell


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