Chapter 3

There are several different types of cables used for transmitting data between computers. You have coaxial cabling, twisted pair cabling, and fiber-optic cabling. 

Coaxial Cable

Coaxial cable was the predecessor for Ethernet networks, but has now been replaced by twisted pair and fiber-optic cabling. The coaxial cable has a copper core that is wrapped in an insulating material that is wrapped in a braided shielding, which is covered by a jacket, which is a plastic material that protects the cable from being damaged.

Twisted Pair Cable

Twisted pair cabling is now the prominent cable used in networking. There are two types of twisted pair cables: STP (shielded twisted pair) and UTP (unshielded twisted pair). 

Shielded twisted pair cable is composed of pairs of twisted wires that are each insulated and covered in a metallic shielding, such as foil or braided copper, which provides a barrier to protect the signal from being affect by electromagnetic forces.

Unshielded twisted pair cable is almost identical to shielded twisted pair, except that it does not contain the shielding that the twisted pair contains. This allows it to be less expensive than STP, however makes it more vulnerable to electromagnetic interference.

Fiber-Optic Cable

Fiber-optic cable is a newer type of cabling that is rapidly growing in popularity due to the faster data speeds that it is capable of, however it is much more expensive than twisted pair due to the cost of materials. It has a core made up of either one or several glass or plastic fibers. The data is transmitted by pulsing light sent from a laser or an LED through the fiber core.The core is surrounded by a layer of plastic or glass known as the cladding. The cladding reflects the light back to the core in various patterns. The reflection allows the light to bend around corners without degrading the signal quality. There are two types of fiber-optic cables: SMF (single-mode fiber) and MMF (multimode fiber). The difference between the two is found in the diameter of the fiber core. Multimode fiber's core has a larger diameter which allows more pulses of light to pass through, allowing more data to be transmitted at a single instance than single-mode fiber.