1. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-1 Introduction to Information Technology. Chapter 6: Telecommunications and Networks

2. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-2 The Telecommunications System  Components include: Hardware Media Networks Software Data comm providers Protocols Applications

3. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-3 Telecommunication Signals  Analog signals  Continuous waves  Information conveyed by changing wave characteristics (amplitude and frequency)  Digital signals  Discrete pulses  Information conveyed in binary form (on or off pulses)  Easily understood by computer

4. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-4 Wire-based Communication Channels  Twisted-pair wire (telephone wire)  Cheap and easy to work with  Slow; subject to interference; low security  Coaxial cable  Carries more data; shielded from interference  More expensive; harder to work with; low security

5. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-5 Wire-based Communication Channels (continued)  Fiber-optic cable  Transmit information as light waves through glass fiber  Fast; high-capacity; secure; not subject to interference

6. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-6 Wireless Communication Channels  Microwave  High capacity; inexpensive relative to wire  Requires line of sight transmission towers; subject to environmental interference  Satellite  Very high capacity; large coverage area  Expensive; propagation delay; requires encryption for security

7. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-7 Understanding Communication Media  Transmission speed  Bandwidth – the range of frequencies available in a channel  More bandwidth, more channel capacity  Transmission mode  Character by character (asynchronous)  Streams of characters (synchronous)  Transmission accuracy  Accuracy controls added to messages  Error detection and correction required

8. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-8 Telecomm Carriers and Services  Telecomm carriers – provide telecomm technology and services for data communication  Common carriers – long-distance phone companies  Value-added carriers – provide private telecomm systems and services for a fee

9. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-9 Network Basics  Network – the communication devices, media, and software needed to connect two or more computer systems.  Local area networks– a network that spans a relatively small geographic distance  Wide area networks – network that spans a large geographic distance

10. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-10 Copyright © 2003 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United Stated Copyright Act without the express written permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information herein. THE END