tailieunhanh - Lecture Using information technology (11/e): Chapter 6 - Brian K. Williams, Stacey C. Sawyer
Chapter 6 - Communications, networks, & cyberthreats. The topics discussed in this chapter are: From the analog to the digital age; networks; wired communications data; wireless communications media; cyberintruders: trolls, spies, hackers, & thieves; cyberattacks & malware; concerns about privacy & identity theft. | Chapter 6 Communications, Networks, & Cyberthreats 1 Chapter Topics 2 UNIT 6A: Networks & Wired & Wireless Data From the Analog to the Digital Age Networks Wired Communications Data Wireless Communications Media UNIT 6B: Cyberthreats, Security, & Privacy Issues Cyberintruders: Trolls, Spies, Hackers, & Thieves Cyberattacks & Malware Concerns about Privacy & Identity Theft Digital convergence is the gradual merger of computing and communications into a new information environment, in which the same information is exchanged among many kinds of equipment, using the language of computers. At the same time, there has been a convergence of several important industries—computers, telecommunications, consumer electronics, entertainment, mass media— producing new electronic products that perform multiple functions. 3 From the Analog to the Digital Age 4 Digital Computers use digital signals—0s and 1s, off and on. All the data that a computer processes is a . | Chapter 6 Communications, Networks, & Cyberthreats 1 Chapter Topics 2 UNIT 6A: Networks & Wired & Wireless Data From the Analog to the Digital Age Networks Wired Communications Data Wireless Communications Media UNIT 6B: Cyberthreats, Security, & Privacy Issues Cyberintruders: Trolls, Spies, Hackers, & Thieves Cyberattacks & Malware Concerns about Privacy & Identity Theft Digital convergence is the gradual merger of computing and communications into a new information environment, in which the same information is exchanged among many kinds of equipment, using the language of computers. At the same time, there has been a convergence of several important industries—computers, telecommunications, consumer electronics, entertainment, mass media— producing new electronic products that perform multiple functions. 3 From the Analog to the Digital Age 4 Digital Computers use digital signals—0s and 1s, off and on. All the data that a computer processes is a series of 0s and 1s. Each signal is a bit. Analog But most phenomena in life are analog. Analog signals use wave variations, continuously changing. Sound, light, and temperature are analog forms. Traditional TV and radio use analog signals. Humans’ vision operates in analog mode. But analog data can be converted into digital form. Even though digital data is not as exact as analog data, it is easier to manipulate. 5 For data transmission over telephone lines and cables, modems are needed to convert analog data into digital data that computers can use. Modem is short for modulate/demodulate. Modems modulate (convert) a computer’s digital data to analog data, transmit it, then demodulate (reconvert) it back to digital data for the receiving computer. Modems can convert data by modulating either a analog wave’s amplitude or its frequency. 6 7 Networks 8 Network: system of interconnected computers, telephones, and/or other communications devices that can communicate with one another and .
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