tailieunhanh - Lecture Data communications and networks: Chapter 7 - Forouzan 

A computer network is designed to send information from one point to another. This information needs to be converted to either a digital signal or an analog signal for transmission. In this chapter, we discuss the first choice, conversion to digital signals. | Chapter 7 Transmission Media Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 7. Figure Transmission medium and physical layer 7. Figure Classes of transmission media 7. 7-1 GUIDED MEDIA Guided media, which are those that provide a conduit from one device to another, include twisted-pair cable, coaxial cable, and fiber-optic cable. Twisted-Pair Cable Coaxial Cable Fiber-Optic Cable Topics discussed in this section: 7. Figure Twisted-pair cable 7. Figure UTP and STP cables 7. Table Categories of unshielded twisted-pair cables 7. Figure UTP connector 7. Figure UTP performance 7. Figure Coaxial cable 7. Table Categories of coaxial cables 7. Figure BNC connectors 7. Figure Coaxial cable performance 7. Figure Bending of light ray 7. Figure Optical fiber 7. Figure Propagation modes 7. Figure Modes 7. Table Fiber types 7. Figure Fiber construction 7. Figure Fiber-optic cable connectors 7. Figure Optical fiber performance 7. 7-2 UNGUIDED MEDIA: WIRELESS Unguided media transport electromagnetic waves without using a physical conductor. This type of communication is often referred to as wireless communication. Radio Waves Microwaves Infrared Topics discussed in this section: 7. Figure Electromagnetic spectrum for wireless communication 7. Figure Propagation methods 7. Table Bands 7. Figure Wireless transmission waves 7. Figure Omnidirectional antenna 7. Radio waves are used for multicast communications, such as radio and television, and paging systems. Note 7. Figure Unidirectional antennas 7. Microwaves are used for unicast communication such as cellular telephones, satellite networks, and wireless LANs. Note 7. Infrared signals can be used for short-range communication in a closed area using . | Chapter 7 Transmission Media Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 7. Figure Transmission medium and physical layer 7. Figure Classes of transmission media 7. 7-1 GUIDED MEDIA Guided media, which are those that provide a conduit from one device to another, include twisted-pair cable, coaxial cable, and fiber-optic cable. Twisted-Pair Cable Coaxial Cable Fiber-Optic Cable Topics discussed in this section: 7. Figure Twisted-pair cable 7. Figure UTP and STP cables 7. Table Categories of unshielded twisted-pair cables 7. Figure UTP connector 7. Figure UTP performance 7. Figure Coaxial cable 7. Table Categories of coaxial cables 7. Figure BNC connectors 7. Figure Coaxial cable performance 7. Figure Bending of light ray 7. Figure Optical fiber 7. Figure Propagation modes 7. Figure Modes 7. Table Fiber .