Twisted Pair Cabling
There are different grades, or categories, of twisted-pair
cabling. Category 5 is the most reliable and widely
compatible, and is required for Fast Ethernet.
You can buy Category 5 cabling that is pre-made, or
you can cut and crimp your own. Category 5 cables can
be purchased or crimped as either straight-through or
crossed. A Category 5 cable has 8 thin, color-coded
wires inside that run from one end of the cable to the
other. Only wires 1, 2, 3, and 6 are used by Ethernet
networks. In a straight-through cable, wires 1, 2, 3, and
6 at one end of the cable are
also wires 1, 2, 3, and 6 at
the other end. In a crossed
cable, the order of the wires
change from one end to the
other: wire 1 be-comes 3,
and 2 becomes 6.
The color code for the 4 wires should be as follows:
Wire 1, white with an orange stripe; Wire 2, orange;
Wire 3, white with a green stripe; Wire 6, green. The
other four wires have to be connected as follows: Wire
4, blue; Wire 5, white with a blue stripe; Wire7, white
with a brown stripe, Wire 8, brown.
To figure out which wire is wire number 1, hold the
cable so that the end of the plastic RJ-
45 tip (the part that goes into a wall
jack first) is facing away from you.
Flip the clip so that the copper side
faces up (the springy clip will now be
parallel to the floor).When looking
down on the coppers, wire 1 will be
on the far left.
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