Computers Are Your Future Eleventh Edition

Computers Are Your Future Eleventh Edition
* 07/16/96 Computers Are Your Future Eleventh Edition Chapter 8: Wired & Wireless Communication Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 2

Wired & Wireless Communication
* 07/16/96 Wired & Wireless Communication This is Figure 8.26. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Objectives Define bandwidth and discuss the bandwidth needs of typical users. Discuss how modems transform digital computer signals into analog signals. List transmission media and explain several transmission methods. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Objectives Explain the limitations of the public switched telephone network (PSTN) for sending and receiving computer data. Describe multiplexing and digital telephony, including their impact on line usage. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Objectives Provide examples of how digitization and convergence are blurring the boundaries that distinguish popular communications devices, including phones and computers. Discuss various wired and wireless applications. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

Moving Data: Bandwidth and Modems
* 07/16/96 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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Moving Data: Bandwidth and Modems Analog signals are continuous waves. Digital signals are discontinuous, discrete pulses. Converters translate signals. This is Figure 8.1. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 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 Hall *

* 07/16/96 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. This is Figure 3.3. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 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 Hall *

Wired Transmission Media
* 07/16/96 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 This is Figure 8.6. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Wired Transmission Media Coaxial cable consists of copper wire surrounded by insulation and braided wire. Broadband communication Cable TV 10 Mbps transfer rate This is Figure 8.7. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 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 This is Figure 8.8. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

Wireless Transmission Media
* 07/16/96 Wireless Transmission Media Infrared is a wireless transmission medium that carries data through the air using light beams. Sending and receiving devices must be in line of sight. Use an IrDA port to enable data transfer. This is Figure 8.9. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 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 Hall *

* 07/16/96 Wireless Transmission Media Microwaves transmit data via electromagnetic radio waves with short frequencies. This is Figure 8.11. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 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 Hall *

Wired Communication via the PSTN
* 07/16/96 Wired Communication via the PSTN Public switched telephone network (PSTN) Worldwide telephone system used for data and voice communications Primarily digital Subscriber loop carrier (SLC) Links home and business telephones Accommodates analog devices Local loop is the area served by an SLC. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Wired Communication via the PSTN Digital telephony Telephones and transmissions are digital. Companies use a private branch exchange (PBX). Multiplexing Allows multiple calls over a single line. Long-distance carriers transmit many calls in digital format in a single circuit. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Wired Communication via the PSTN Last-mile technologies Provide solutions for bottlenecks that result from the inability of users to access the PSTN’s high-speed fiber-optic cables Used while local loops are upgraded Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Wired Communication via the PSTN Last-mile technologies Integrated services digital networking (ISDN) Standard that provides digital telephone and data service No lengthy dial-in procedures or connection delay Requires an ISDN adapter/digital modem to connect computers to ISDN lines May be the only broadband solution in rural areas Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Wired Communication via the PSTN Last-mile technologies Digital subscriber line (DSL) Broad term for a group of technologies that offer high-speed access to the Internet Requires a DSL modem to modulate and demodulate analog and digital signals More expensive than dial-up but cheaper than other broadband options Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Wired Communication via the PSTN Last-mile technologies Cable-based broadband Provides Internet access through cable TV connections Uses cable modems to obtain higher speeds than DSL Leased lines Specially conditioned telephone lines, such as T1 lines, between two points Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Wired Communication via the PSTN Last-mile technologies T3 lines SONET (synchronous optical network) MMDS (Multichannel multipoint distribution service) WiMax (Worldwide interoperability for microwave access) Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

Convergence: Is It a Phone or a Computer?
* 07/16/96 Convergence: Is It a Phone or a Computer? Digitization is the process of transforming data into a digital form. Convergence is blending: Multiple industries such as computers, consumer electronics, and telecommunications Products such as personal computers and telephones This is Figure 8.17a. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Convergence: Is It a Phone or a Computer? Cellular telephones Digital transmission of voice, text, images, and video. Classified by generations; 3G (third generation) is the current generation. A network of transmitters called cell sites broadcasts signals throughout geographic areas called cells. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Convergence: Is It a Phone or a Computer? Each cellular network includes multiple mobile switching centers (MSCs) that control communication within a set of cells. This is Figure 8.19. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Convergence: Is It a Phone or a Computer? Personal communication service (PCS) is a group of digital cellular technologies that replaced most analog cellular services. 2G (second generation) design specifications used to make smartphones, which combine the features of phones and computing devices. 3G supports more data and voice customers and higher data transfer rates. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Convergence: Is It a Phone or a Computer? 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 Hall *

Wired and Wireless Applications
* 07/16/96 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 Hall *

* 07/16/96 Wired and Wireless Applications Internet telephony Videoconferencing transmits sound and video images to people in different locations using: Video camera Skype software This is Figure 8.26. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 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 Hall *

* 07/16/96 Wired and Wireless Applications Satellite technology Satellite radio Is not affected by location, distance, or obstructions Uses satellites orbiting the Earth Permits usage in areas with restricted local radio stations or bad AM/FM reception Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 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 Hall *

* 07/16/96 Wired and Wireless Applications Text and picture messaging Text messaging is using a cell phone for applications previously used on computers Instant messaging Brief This is Figure 3.32. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Wired and Wireless Applications Text and picture messaging Picture messaging Transmits color pictures and backgrounds Cellular telephone acts as a camera Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Wired and Wireless Applications Surfing safely at public wireless hot spots Use firewalls and antivirus software. Use legitimate networks to avoid “evil twins.” Do not perform financial transactions. Select appropriate operating system settings to avoid being detected. This is Figure 3.29. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Summary Bandwidth refers to the maximum data transfer capacity of a communication channel. Modems are used to modulate and demodulate data sent over dial-up phone lines. Communications involve both wired and wireless media. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Summary Use of the PSTN, which is mostly digital, is decreasing because of the increase in the use of broadband alternatives. Multiplexing is the sending of multiple telephone calls or messages on a single line. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Summary Digitization is the conversion of voice, text, graphic, audio, and video data into a digital format. Convergence is the merging of products, such as phones and computers. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

* 07/16/96 Summary Traditional wired technology can be used for VoIP and faxing, whereas wireless technology makes text and picture messages, satellite radios, and GPS services possible. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall *

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