Cisco SR224 User Guide - Page 34

24-port 10/100 + 2-Port Gigabit Switch with WebView Appendix B: Cabling Overview Twisted Pair Cabling and Fiber Optic Cabling are discussed in this appendix. Twisted Pair Cabling There are different grades, or categories, of twisted-pair cabling. Category 5 is the most reliable and is highly recommended. 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 information 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 looking down on the copper side, wire 1 will be on the far left. Crimping your own Network Cables The processes for straight-through cabling and crossed-over cabling are illustrated below. Figure B-1: Cable Charts Appendix B: Cabling 28 Overview