1. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-1 Introduction to Information Technology 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. Chapter 6: Telecommunications and Networks Prepared by: Roberta M. Roth, Ph.D. University of Northern Iowa

2. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-2 Chapter Preview  In this chapter, we will study:  The basic components of a telecomm system  The technologies used in telecomm systems  Various ways to configure networks  Various ways that businesses use networks today

3. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-3 The Telecommunications System  The hardware and software that transmits information from one location to another  Components include:  Hardware  Media  Networks  Software  Data comm providers  Protocols  Applications

4. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-4 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

5. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-5 Communication Processors  Hardware devices utilized in data transmission and reception  Modem - device that converts analog signals to digital (and vice versa); enables signal transmission over telephone system  Multiplexor - device that transmits multiple signals over single medium  Front-end processor – specialized computer dedicated to managing communication tasks

6. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-6 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

7. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-7 Wire-based Communication Channels (continued)  Fiber-optic cable  Transmit information as light waves through glass fiber  Fast; high-capacity; secure; not subject to interference  Hard to work with

8. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-8 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

9. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-9 Wireless Communication Channels (continued)  Radio  Suitable for short distance communication; inexpensive; easy to install; high speed  Interference problems; insecure  Cellular radio technology  Infrared

10. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-10 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

11. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-11 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

12. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-12 Telecomm Carriers and Services (continued)  Telecomm services  Switched lines – transmission is routed along path to destination  Dedicated lines – continuous connection is established  Wide-area Telecomm Service (WATS) – lower cost long distance telephone service  Integrated Services Digital Network (ISDN) – high speed data transmission over existing phone lines  Digital Subscriber Lines (DSL) - high speed digital transmission over existing phone lines

13. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-13 Network Basics  Network – the communication devices, media, and software needed to connect two or more computer systems.  Local area networks (LANs) – a network that spans a relatively small geographic distance  Wide area networks (WANs) – network that spans a large geographic distance

14. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-14 Local Area Networks  Connect computers and other devices enabling resource sharing  Variety of topologies can be used, each with performance strengths and weaknesses  Several LANs can be connected via bridges  LANs can be connected to external networks via gateways

15. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-15 LAN Basics  Required technology:  Cables or wireless technology  Network interface adaptor cards  Network management software  Chosen topology is implemented by selection of software, interface cards, and wiring strategy.

16. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-16 Wide Area Networks  Service provided by common carriers  Internet is a public WAN  Value-added networks (VAN) – private, data-only networks managed by third party; accessed via subscription.  Virtual private network (VPN) – secure gateway between corporate systems and the Internet.

17. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-17 Network Communication Software  Needed to provide a number of network functions:  Check for errors  Format messages  Maintain communication logs  Ensure data security and privacy  Provide message translation

18. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-18 Network Communication Software (continued)  Components  Network Operating System – enables all devices on network to communicate  Network Management Software – simplifies human network management tasks  Protocols – specify rules that govern device communication over the network

19. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-19 Network Communication Software (continued)  Types of Protocols  Ethernet Most common protocol May be 10BaseT (10 Mbps); Fast Ethernet 100BaseT (100Mbps); Gigabit Ethernet (1Gbps)  Transmission Control Protocol/Internet Protocol (TCP-IP) Sends large files accurately over different systems Standard of the Internet

20. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-20 Network Communication Software (continued)  Data Transmission Options to improve network performance  Packet-switching  Frame relay  Fiber Distributed Data Interface (FDDI)  Asynchronous Transfer Mode (ATM)  Switched Hub Technologies  Synchronous Optical Network (SONET)  T-carrier System

21. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-21 Network Processing Strategies  IS managers strive to provide good network response time and network availability  Distributed processing enables computers in various locations to communicate over telecomm links  Terminal-to-host processing  File server processing  Client/server architecture and processing

22. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-22 Network Processing Strategies (continued)  Client/server processing  Applications can be divided into presentation, applications, and data management components  Components can be partitioned between the server and the clients to form different implementations

23. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-23 Network Processing Strategies (continued)  Peer-to-peer processing  Simplified form of client/server  Devices attached to network have access to all other devices  No file server involved  Simple set up and maintenance  Implemented in many operating systems such as Windows 2000 and Windows XP

24. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-24 Network Processing Strategies (continued)  Open Systems – ideal not fully achieved  Any device can be seamlessly connected to any other device, regardless of size, operating system, or application  Connectivity – ability of computer resources to communicate without human intervention  Enterprise-wide network – spans entire organization because of open systems and connectivity

25. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-25 Telecomm Applications  Electronic Mail – computer- based messaging  Videoconferencing – group meetings between separate locations  Electronic Data Interchange – electronic transmission of routine business transactions  Electronic Funds Transfer – electronic processing of financial transactions  Facsimiles – electronic document transmittal  Telecommuting – working at home via telecomm links  Distance Learning – classes offered on same time/different place, or different time/ different place basis  Telematics

26. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-26 Chapter Summary  Components of a telecomm system  Types of communication media used in telecomm systems  Types of networks  Ways to organize network processing  Ways to utilize networks in businesses today

27. Introduction to Information Technology, 2 nd Edition Turban, Rainer & Potter © 2003 John Wiley & Sons, Inc. 6-27 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.