Brief Guide To Cabling

In this section we will discuss the various network components which make up a network. We will discuss the cabling types, patch, patch panels, connectors etc.Brief Guide to BUILDING WIRINGThe following is a very brief overview of the components that make up the wiring standards for commercial buildings. The objectives of such standards is to:computer define a generic voice and data wiring system that is multi-purpose and multi-vendorcomputerhelp minimise cost of administrationcomputersimplify network maintenance and changesA building wiring system covers a number of different elementscomputerhorizontal wiringcomputerbackbone wiringcomputerHorizontal WiringThe horizontal wiring extends from the wall outlet to the system centre (telecommunications closet). It includes the:computerthe wall outletcomputerthe horizontal cablecomputercross-connects or patch cables in the telecommunications closet (TC)Some general features of the horizontal wiring scheme are: computeruses star topologycomputerlimit of 90 meters (295') from TC to wall outletcomputerlimit of 3 meters (10') to connect from wall outlet to PCcomputerpatch cords and cross-connect leads are limited to 6 meters (20')computerminimum of two outlets per user (phone+data)computerstandardized media, Outlet A=4pair 100ohm UTP, Outlet B=same or 2 pair 150ohm STPBackbone WiringThe backbone wiring system interconnects telecommunication closets, equipment rooms and entrance facilities (ie, the outside world). Some general features are:computer star topologycomputermaximum of two hierarchical levelscomputerinterconnections between any two TC must not go through more than 3 cross connectscomputeruse of recognised mediacomputeradherence to distance limitationsCabling Typescomputer Twisted Pair (STP and UTP)computerused in token ring (4 or 16MB/s), 10BaseT (Ethernet 10MB/s)computercheapcomputereasy to terminatecomputerUTP often already installed in buldingscomputerUTP prone to interferencecomputerlow to medium capacitycomputermedium to high losscomputercategory 3 = 10MB/s, category 5 = 100MB/sUnshielded Twisted Pair cable used in Category 5 looks like:Category 5 cable uses 8 wires. The length of exposed wires is very critical, the standard limits this to less than 1/2" an inch. The various jack connectors look like:The patch cord which connects the workstation to the wall jack looks like:In 10BaseT, each PC is wired back to a central hub using its own cable. There are limits imposed on the length of drop cable from the PC network card to the jack, the length of the horizontal wiring, and from the jack to the wiring closet.This is obviously a physical STAR configuration, in that each PC is wired back to a central point (the Hub).Ethernet 10Base-T wiring specifies an 8 position jack, but uses only two pairs.

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