Computers Are Your Future Eleventh Edition Chapter 8: Wired & Wireless Communication Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall1

Wired & Wireless Communication 2Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

Moving Data: Bandwidth and Modems Communications is the process of sending and receiving messages electronically between two points. A communications channel is a path used to send and receive messages. 3Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

Network Fundamentals LAN Uses cables, radio waves, or infrared signals Links computers in a limited geographic area WAN Uses long-distance transmission media Links computer systems a few miles or thousands of miles apart The Internet is the largest WAN Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall4

Moving Data: Bandwidth and Modems Analog signals are continuous waves. Digital signals are discontinuous, discrete pulses. Converters translate signals. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall5

Moving Data: Bandwidth and Modems Bandwidth is the maximum amount of data transmitted through a communication channel at one time. Throughput is the actual amount of data transmitted. Broadband is any transmission medium that carries several channels to transport data at high speeds. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall6

Moving Data: Bandwidth and Modems A modem is a communication device used to send and receive data between different transmission systems. The sender uses modulation to transmit digital signals. The receiver uses demodulation to return signals to digital form. The term modem comes from modulate and demodulate. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall7

Moving Data: Bandwidth and Modems Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall8

Moving Data: Bandwidth and Modems Types of modems Analog Digital subscriber line (DSL) Cable Integrated Services Digital Network (ISDN) The data transfer rate—the rate at which two modems exchange data—is measured in bits per second (bps). Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall9

Wired Transmission Media Twisted pair wire is copper wire used for telephone and data communication. Two pairs of interweaved wires twisted together Inexpensive, but bandwidth too low for video, voice, and data at the same time Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall10

Wired Transmission Media Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall11 Coaxial cable consists of copper wire surrounded by insulation and braided wire. Broadband communication Cable TV 10 Mbps transfer rate

Wired Transmission Media Fiber-optic cable consists of thin strands of glass or plastic that carry data through pulses of light. Broadband communication 10 Gbps transfer rate Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall12

Wireless Transmission Media Sending and receiving devices must be in line of sight. Use an IrDA port to enable data transfer. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall13 Infrared is a wireless transmission medium that carries data through the air using light beams.

Wireless Transmission Media Radio transmission enables music, photos, and voice to travel through the air as radio frequency or radio waves. Bluetooth radio transmission enables devices within 30 feet to communicate wirelessly. Does not require direct line of sight. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall14

Wireless Transmission Media Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall15

Wireless Transmission Media Microwaves transmit data via electromagnetic radio waves with short frequencies. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall16

Wireless Transmission Media Satellites are microwave relay stations in space that transmit data through microwave signals. Direct broadcast satellite (DBS) is a consumer satellite technology that receives digital TV signals through a reception dish. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall17

Web-enabled devices Display and respond to markup languages, such as HTML and XML, that are used to build Web pages. Examples PDAs Smartphones Notebooks Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall18 Convergence: Is It a Phone or a Computer?

Wired and Wireless Applications Internet telephony, or VoIP (Voice over Internet Protocol) Offers computer-to-phone and phone-to- phone transmission through the Internet Placing calls requires: A computer with a microphone and speakers or headphones An Internet connection A telephone-enabled program Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall19

Wired and Wireless Applications Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall20 Internet telephony Videoconferencing transmits sound and video images to people in different locations using: Video camera Skype software

Wired and Wireless Applications Facsimile transmission (fax) transmits documents over a telephone line or the Internet using either: A standalone fax machine, or A computer with a fax modem and a scanner Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall21

Wired and Wireless Applications Satellite technology GPS (Global Positioning System) A system of 27 satellites that allows a GPS receiver to pinpoint a location Mobile units for cars Installed car systems, such as OnStar Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall22

Wired and Wireless Applications Text messaging is using a cell phone for applications previously used on computers Instant messaging Brief Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall23 Text and picture messaging

Wired and Wireless Applications Picture messaging Transmits color pictures and backgrounds Cellular telephone acts as a camera Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall24 Text and picture messaging

Wired and Wireless Applications Surfing safely at public wireless hot spots Use firewalls and antivirus software. Do not perform financial transactions. Select appropriate operating system settings to avoid being detected. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall25