Network Media Types
Upon completing this chapter, you will be able to:
• • • • •
Describe the primary types and uses of twisted-pair cables Describe the primary types and uses of coaxial cables Describe the primary types and uses of fiber-optic cables Describe the primary types and uses of wireless media Compare and contrast the primary types and uses of different media
CHAPTER
8
Network Media Types
Network media is the actual path over which an electrical signal travels as it moves from one component to another. This chapter describes the common types of network media, including twisted-pair cable, coaxial cable, fiber-optic cable, and wireless.
Twisted-Pair Cable
Twisted-pair cable is a type of cabling that is used for telephone communications and most modern Ethernet networks. A pair of wires forms a circuit that can transmit data. The pairs are twisted to provide protection against crosstalk, the noise generated by adjacent pairs. When electrical current flows through a wire, it creates a small, circular magnetic field around the wire. When two wires in an electrical circuit are placed close together, their magnetic fields are the exact opposite of each other. Thus, the two magnetic fields cancel each other out. They also cancel out any outside magnetic fields. Twisting the wires can enhance this cancellation effect. Using cancellation together with twisting the wires, cable designers can effectively provide self-shielding for wire pairs within the network media. Two basic types of twisted-pair cable exist: unshielded twisted pair (UTP) and shielded twisted pair (STP). The following sections discuss UTP and STP cable in more detail.
UTP Cable
UTP cable is a medium that is composed of pairs of wires (see Figure 8-1). UTP cable is used in a variety of networks. Each of the eight individual copper wires in UTP cable ¥is covered by an insulating material. In addition, the wires in each pair are twisted around each other.
Figure 8-1
Unshielded Twisted-Pair Cable
• • • • •
Describe the primary types and uses of twisted-pair cables Describe the primary types and uses of coaxial cables Describe the primary types and uses of fiber-optic cables Describe the primary types and uses of wireless media Compare and contrast the primary types and uses of different media
CHAPTER
8
Network Media Types
Network media is the actual path over which an electrical signal travels as it moves from one component to another. This chapter describes the common types of network media, including twisted-pair cable, coaxial cable, fiber-optic cable, and wireless.
Twisted-Pair Cable
Twisted-pair cable is a type of cabling that is used for telephone communications and most modern Ethernet networks. A pair of wires forms a circuit that can transmit data. The pairs are twisted to provide protection against crosstalk, the noise generated by adjacent pairs. When electrical current flows through a wire, it creates a small, circular magnetic field around the wire. When two wires in an electrical circuit are placed close together, their magnetic fields are the exact opposite of each other. Thus, the two magnetic fields cancel each other out. They also cancel out any outside magnetic fields. Twisting the wires can enhance this cancellation effect. Using cancellation together with twisting the wires, cable designers can effectively provide self-shielding for wire pairs within the network media. Two basic types of twisted-pair cable exist: unshielded twisted pair (UTP) and shielded twisted pair (STP). The following sections discuss UTP and STP cable in more detail.
UTP Cable
UTP cable is a medium that is composed of pairs of wires (see Figure 8-1). UTP cable is used in a variety of networks. Each of the eight individual copper wires in UTP cable ¥is covered by an insulating material. In addition, the wires in each pair are twisted around each other.
Figure 8-1
Unshielded Twisted-Pair Cable