Cat-5 Ethernet cable The cable used on an Ethernet network is described as UTP cable, which stands for unshielded twisted pair. Inside, the cable has eight cable cores arranged as four twisted pairs, but unlike with audio and video cables, there is no foil shielding around the inner cores. It is the twisting alone that provides a degree of isolation from interference from outside the cable and, allows the cable to carry data at very high rates up to a distance of 100 meters (300 feet). Often, the cable is named by its specification schedule of Category-5 (think of the worse hurricane level), which is abbreviated to Cat-5 or Cat-5E. Network cable is terminated with an RJ45 module (wall socket) or, an RJ45 plug. Cat-6 cable is very similar, but will allow even faster data transmission rates. Each length of Cat-5 cable can run to 100 meters (300 feet) RJ45 8P8C connectors Ethernet cables are terminated with RJ45 connectors. Often termed an 8P8C connector, this means there are eight positions which are occupied by eight contacts and, it fits into a socket called a module. When viewed end-on, RJ45 connectors are oblong. Do not confuse this connector with it's cousin, the RJ11 connector. The RJ11 standard, also called 6P4C, is widely used to connect DSL routers to telephone lines. An RJ11 plug when viewed end-on is square-ish not oblong. The smaller 4P4C connector is used for American telephone cables. See the diagram below for the RJ45 connector wiring plan. There is no need to strip the eight cables bare before they are located inside the connector. The plug contacts have teeth that bite through the insulation in a technique called insulation displacement. The contacts must be punched down firmly in order to make a reliable contact. An RJ45 crimping tool is a worthwhile investment as it crimps all eight contracts at once. An automated cable tester is a nice-to-have accessory as it tests each conductive line at once. Should for some reason, the connector fail to make, it is often best to cut off the failed end and start again. A small bag of 8P8C connectors is a wise purchase. Never push an uncrimped connector into a module. The still proud contacts will foul the contact tangs, and prove a real nuisance to remove. That's experience talking. A correctly assembled RJ45 connector Untwisting the cable pairs will cause the cable to lose its high speed data integrity Although unnecessary for most inside wiring jobs, RJ45 connectors can be covered using protective boots. Available in a range of colours, boots are suitable for colour coding the otherwise grey and buff cables. When assembling ad-hoc cables, snag-less boots are preferable. Pictured, an ordinary booted connector (top) and a snag-less boot. See how the blue boot covers the locking tab on the RJ45 connector. This prevents the tab acting like a fishing barb, snagging and then dragging on every other cable in creation. Put boots on the cable before crimping the connectors! RJ45 8P8C connector wiring plan Cat-5 cable colours and their corresponding place within the 8P8C connector. Both connectors at either end of the cable are wired in exactly the same way, making two identical looking plugs. So is there actually a need to over-loop the solid green and solid blue coloured cables? The answer is no. In technical terms, provided the cable colour at each position on both connectors is the same, there is no need for over-looping. This is because the devices at either end have no idea of the colour of the insulation being used! Only pedantic inspectors might. Where there is a need to make-up custom network leads, a few inexpensive tools are a worthwhile and stress-busting expenditure. Pictured, the blue handled device is an RJ45 crimping tool. The grey boxes are both ends of an automated cable continuity tester. The red handled clippers are for cutting a clean edge on the Cat-5 cable so the strands will insert into the RJ45 connector without scrunching.