RJ45

The wires used for a LAN are mostly those headed by an RJ45 jack, which is similar to the jack plugged into your telephone set, but twice as big. Some Ethernet networks use coaxial cables, but that’s rarer, and present in rather large LANs, which span over areas between buildings. If you want to see what a coaxial cable is like, look at the thick cable that links your TV antenna to your TV set.

Ethernet is by far the most popular LAN protocol used today. It is so popular that if you buy a network card to install on your machine, you will get an Ethernet card, unless you ask for something different, if of course that different protocol is available.

Ethernet has evolved over the years. Today, you can get cheap Ethernet LAN cards with speeds up to 100 Mbps; while the fastest Ethernet reaches Gbps (1 Gbps = 1000 Mbps) in speed.