10/100 Hubs
9
Instant EtherFast II Series
Appendix
There are different grades, or categories, of twisted-pair cabling. Category 5
is the most reliable and is highly recommended. Category 3 is a good second
choice. Straight-through cables are used for connecting computers to a hub.
Crossover cables are used for connecting a hub to another hub (there is an
exception: some hubs have a built-in uplink port that is crossed internally,
which allows you to link or connect hubs together with a straight-through
cable instead).
You can buy pre-made Category 5
cabling, or cut and crimp your own.
Category 5 cables can be purchased
or crimped as either straight-through
or crossover cables. A Category 5
cable has 8 thin, color-coded wires
inside that run from one end of the
cable to the other. All 8 wires are
used. 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 crossover cable,
the order of the wires change from
one end to the other: wire 1 becomes
3, and 2 becomes 6. See the diagrams
on the next page for
more detailed informa-
tion on straight-through
and crossover cabling.
To determine 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.
Face the clip down so that the copper side faces up (the
springy clip will now be parallel to the floor).When look-
ing down on the copper side, wire 1 will be on the far
left.
8
Twisted-Pair Cabling
Crimping Your Own Network Cables
Cross-Over Cabling
Straight-Through Cabling
