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UTP Ethernet Ethernet is often used to build a network of computers in home and office situations. Today UTP Ethernet is the preferred method to connect the computers with the rest of the network. Several standards exist to accommodate different transfer speeds. The basics remain the same however, no matter what speed is used. Two network speeds are common today. 10baseT networks have a transmission speed of 10Mbits/second. And 100baseTX networks, which have a transmission speed of 100Mbits/second. Even Gigabit network equipment is quite affordable these days. For Gigabit networks you need at least CAT-5e or CAT-6 cable. Cable Properties UTP stands for Unshielded Twisted Pairs. Such a cable consists of 4 pairs of wires, where each pair is constantly twisted along the total length of the cable. This twisting is very important, for it ensures interference immunity and low radiation emission. The overall quality of the cable is very important, especially if you want to run the network at 100Mbit/sec and beyond. For 10Mbit/sec speeds you can use CAT-3 cables, but if you want to run your network at 100Mbit/sec CAT-5 cable is required. My advice is always to use at least CAT-5e cable quality, regardless of your current network speed.  Connectors UTP Ethernet uses RJ-45 connectors. These are crimp connectors, with 8 contacts. They are quite similar to telephone connectors but have a few more contacts. You need a special crimping tool to mount the connectors to the cable. If you intend to make more than a few cables in the future youd better buy a decent crimping tool. The plastic versions usually dont live very long. When you crimp the connector to the cable be sure that all wires run all the way to the end of the connector and that the cables sleeve is caught by the latch. Connections The actual communication over a UTP Ethernet is done over two wire pairs. One pair is used for sending (TX), the other pair is used for receiving (RX). The TX side from one