There are a number of different types of ethernet cable, as ethernet has been around for a long time.
These days, "ethernet cable" usually refers to Unshielded Twisted Pair (UTP) and one of cat5 (category 5), cat5e (category 5 enhanced) or cat6 (category 6).
As a rough guide, cat 5 is a medium for speeds up to 100Mbps, cat 5e is capable of speeds up to 1000Mbps. Cat5 and cat5e cables can be used for distances up to 100 meter without the use of repeaters. Cat6 is the new standard for ethernet cable used, which makes even faster network traffic possible.
If you only want two devices, it is possible to connect them directly by using a crossover cable. This is a normal UTP cable that has the send and receive wires crossed over at each end.
Older networks may use coaxial cable, which is like TV aerial wire, and has a Bayonet Nut Connector (BNC) on the end. The coaxial cables used for ethernet come in two flavors.
- thinnet (10Base-2), Speed: 10Mbps Range: 185m
- thicknet (10Base-5), Speed: 10Mbps Range: 500m
Coaxial networks need a resistor, called terminator, in both ends of the cable in order to work. Without terminator the signal bounces back and forth in the cable and mess up the communication.