Local Area Networking - Notes 2
Cable pinout Information found on the Linksys web site.
| 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 for
communication. Although only four wires are used, if the cable has 8
wires, all the wires have to be connected in both jacks.
Straight-through cables are used for connecting computers to a hub. Crossed 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 uplink hubs together with a straight cable instead). 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 becomes 3, and 2 becomes 6. 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. |
