Computers Are Your Future Twelfth Edition Chapter 8: Wired and Wireless Communication Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 1

Wired and Wireless Communication Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall2

Moving Data: Bandwidth and Modems Communications o Process of sending and receiving messages electronically between two points Communications channel o Path to send and receive messages Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 3

Moving Data: Bandwidth and Modems Bandwidth o The maximum amount of data transmitted through a communication channel at one time o Measured in Bits per Second (bps) Throughput o The actual amount of data transmitted Broadband o Any transmission medium that transports data at high speeds Streaming o The ability to hear or see content while it is being downloaded from a Web site Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 4

Moving Data: Bandwidth and Modems Analog signals o Continuous waves Digital signals o Discontinuous, discrete pulses Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 5

Moving Data: Bandwidth and Modems Modem o Communications device to send and receive data o Modem comes from modulate and demodulate. Modulate- Converts digital to analog signals. Demodulate – Converts analog to digital signals. Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 6

Moving Data: Bandwidth and Modems Types of modems o Analog o Digital subscriber line (DSL) o Cable Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 7

Digital subscriber line (DSL) Technologies that offer high-speed access Needs DSL modem—modulate and demodulate analog and digital signals More expensive than dial-up—cheaper than other broadband options Wired Communication Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 8

Wired Transmission Media Wired Technologies Connected by a physical medium Twisted-pair wire o Copper wire used for telephone and data communication o Inexpensive, but bandwidth too low for video, voice, and data at the same time Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 9

Wired Transmission Media Coaxial cable o Consists of copper wire surrounded by insulation and braided wire Broadband communication Cable TV 10 Mbps transfer rate Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 10

Wired Transmission Media Fiber-optic cable o Thin strands of glass or plastic that carry data through pulses of light Broadband communication 10 Gbps transfer rate Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 11

Cable-based broadband o Provides Internet access through cable TV connections o Uses cable modems to obtain higher speeds than DSL Leased lines o Specially conditioned telephone lines between two points that allows end-to-end communications o Example: T1 lines Wired Communication Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 12

Wireless Transmission Media Infrared o Wireless transmission medium that carries data through the air using light beams o Must have clean line of sight Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 13

Wireless Transmission Media Radio transmission o Enables music, photos, and voice to travel through the air as radio frequency or radio waves o Bluetooth—radio transmission enables devices within 30 feet to communicate wirelessly Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 14

Wireless Transmission Media Microwaves o Transmit data via electromagnetic radio waves with short frequencies Satellites o Microwave relay stations in space that transmit data through microwave signals to the Earth o Direct satellite –consumer receives digital TV signals through a reception dish Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 15

Convergence: Is It a Phone or a Computer? Convergence o Blending o Phone and Web Access o Products o Examples: Personal computers, telephones Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 16

Cellular telephones o Digital transmission of voice, text, images, and video o Classified by generations—4G (fourth generation)—the current generation improved connectivity, data transfer rates, and support for the next generation of multimedia o Cell sites—network of transmitters broadcasts signals throughout geographic areas called cells Convergence: Is It A Phone or A Computer? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 17

Each cellular network includes multiple mobile switching centers (MSCs) that control communication within a set of cells. Convergence: Is It A Phone or A Computer? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 18

Wired and Wireless Applications Internet telephony, or VoIP (Voice over Internet Protocol) o Offers computer-to-phone and phone-to-phone transmission through the Internet o Placing calls requires: Computer with a microphone, speakers or headphones Internet connection o Free Long Distance Calls Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 19

Wired and Wireless Applications Internet telephony o Videoconferencing (Web conferencing)—transmits sound and video images using: Video camera (Webcams) Skype software o Webcams—inexpensive, low-resolution analog or digital video cameras Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 20

Wired and Wireless Applications Satellite technology (con’t.) o GPS (Global Positioning System) System of 27 satellites allowing a receiver to pinpoint locations Mobile units for cars Installed car systems Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 21

Wired and Wireless Applications Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 22

Wired and Wireless Applications Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 23

Wired and Wireless Applications Text messaging (SMS) o Instant messaging Picture messaging o MMS (multimedia messaging system) Location awareness o Uses GPS-enabled chips to pinpoint the location of a cell phone o Popular with parents of teenagers Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 24

Wired and Wireless Applications Surfing safely at public wireless hot spots o Malicious network (evil twin)—network set up by a hacker within the operating area of a legitimate hot spot o Use firewalls and antivirus software o Do not perform financial transactions Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 25