1. Management Information Systems, 3 rd Edition Effy Oz 1 Chapter 6 Information Technology in Business: Telecommunications and Networks

2. Management Information Systems, 3 rd Edition Effy Oz 2 Learning Objectives When you finish this chapter, you will: –Recognize why successful managers must be familiar with telecommunications concepts and terminology. –Know the principles of communication within a computer system and among computers. –Be able to identify the major media and devices that are used in telecommunications.

3. Management Information Systems, 3 rd Edition Effy Oz 3 Learning Objectives –Be able to list and explain the functions of different network layouts and the concept of protocols. –Understand how telecommunications can improve operations in organizations. –Know the latest developments in telecommunications media and transmission speeds.

4. Management Information Systems, 3 rd Edition Effy Oz 4 Telecommunications in Business Telecommunications –Transmittal of data from one computer to another over a distance Telecommunications has brought four basic improvements to business process: –Better communication –Higher efficiency –Better distribution of data –Instant transactions

5. Management Information Systems, 3 rd Edition Effy Oz 5 Data Communications –Any transfer of data within a computer, between a computer and another device, or between two computers

6. Management Information Systems, 3 rd Edition Effy Oz 6 Types of Data Communications Two Basic Modes –Parallel transmission Each byte is transmitted in its entirety Parallel port –Serial transmission Data are transmitted one bit at a time through a single line Serial port

7. Management Information Systems, 3 rd Edition Effy Oz 7 Communication Direction Three Modes of Communication Between Devices –Simplex One-way in one direction –Half-Duplex One-way in two directions –Full-Duplex Two-way in two directions

8. Management Information Systems, 3 rd Edition Effy Oz 8 Communication Direction Figure 6.2 Simplex, half-duplex, and full-duplex communication

9. Management Information Systems, 3 rd Edition Effy Oz 9 Synchronization Asynchronous Communication –In asynchronous transmission, the devices are not synchronized by any timing aids. –Advantage of asynchronous transmission Does not need sophisticated and expensive timing hardware –Disadvantage of asynchronous transmission Overhead, time spent transmitting bits that are not a part of the primary data

10. Management Information Systems, 3 rd Edition Effy Oz 10 Synchronization Synchronous Communication –In synchronous communication, data are transmitted using timing devices. –Messages are transmitted in packets. –Advantage of synchronous communication Overhead in synchronous communication is significantly smaller than in asynchronous communication.

11. Management Information Systems, 3 rd Edition Effy Oz 11 Communication Modes Figure 6.4 Synchronous transmission

12. Management Information Systems, 3 rd Edition Effy Oz 12 Channels and Media Communication Channel –Physical medium through which data can be communicated. Capacity –Speed at which data are communicated Channel Capacity –Narrow band –Broadband

13. Management Information Systems, 3 rd Edition Effy Oz 13 Channels and Media Figure 6.5 Transmission speed measurement unit

14. Management Information Systems, 3 rd Edition Effy Oz 14 Channels and Media Media –A medium is any means by which data can be transmitted. Transmission speed –A medium’s capacity is determined by the range of bits per second at which it can operate.

15. Management Information Systems, 3 rd Edition Effy Oz 15 Channels and Media Figure 6.6 Telecommunications transmission speeds of different media

16. Management Information Systems, 3 rd Edition Effy Oz 16 Channels and Media Twisted Pair –Telephone line made of a pair of copper wires twisted to reduce electromagnetic interference (EMI) Coaxial Cable –Commonly used for cable television transmission More expensive than twisted pair Greater transmission rate than twisted pair Much less susceptible to EMI

17. Management Information Systems, 3 rd Edition Effy Oz 17 Channels and Media Microwaves –High-frequency, short radio-frequency (RF) waves Terrestrial microwave Satellite microwave Optical Fiber –Fiber-optic technology uses light instead of electricity to transmit data.

18. Management Information Systems, 3 rd Edition Effy Oz 18 Channels and Media Figure 6.7 Characteristics of channel media

19. Management Information Systems, 3 rd Edition Effy Oz 19 Modulation –Analog vs. Digital Analog signals –A continuous series of waves Digital signals –A series of discrete bits

20. Management Information Systems, 3 rd Edition Effy Oz 20 Modulation –Modulation Modification of a digital signal into an analog signal –Demodulation Modification of an analog signal into a digital signal

21. Management Information Systems, 3 rd Edition Effy Oz 21 Modulation Figure 6.8 Signal modulation

22. Management Information Systems, 3 rd Edition Effy Oz 22 Modulation Amplitude Modulation (AM) Frequency Modulation (FM) Phase Modulation

23. Management Information Systems, 3 rd Edition Effy Oz 23 Modulation Modems –Devices that modulate and demodulate signals Set-Up Fas/Voice Multiplexers –Devices that allow several telephones or computers to transmit data through a single line Frequency division multiplexing Time-division multiplexing

24. Management Information Systems, 3 rd Edition Effy Oz 24 Modulation Figure 6.9 Multiplexing

25. Management Information Systems, 3 rd Edition Effy Oz 25 Modulation Figure 6.10 Frequency division

26. Management Information Systems, 3 rd Edition Effy Oz 26 Networks LANs (Local Area Networks) –Networks within a building, or within a group of adjacent buildings WANs (Wide Area Networks) –Networks that cross organizational boundaries or reach outside the company Value-added networks (VANs) Wireless communication

27. Management Information Systems, 3 rd Edition Effy Oz 27 Networks Figure 6.11 Where wireless LANs are a good choice

28. Management Information Systems, 3 rd Edition Effy Oz 28 Networks Network Topology –Physical layout of the nodes in a network Star Ring Bus Tree

29. Management Information Systems, 3 rd Edition Effy Oz 29 Network Topology Figure 6.12 Network topologies

30. Management Information Systems, 3 rd Edition Effy Oz 30 Network Topology Virtual Private Networks (VPN) –Combination of public and private lines LAN is a private network (only provides access to members of an organization)

31. Management Information Systems, 3 rd Edition Effy Oz 31 Protocols Communication protocols –Rules governing the communication between computers or between computers and other computer-related devices Network protocols –Rules governing a network of devices

32. Management Information Systems, 3 rd Edition Effy Oz 32 Protocols Figure 6.13 Some communications software allows a user to establish protocols: bit rate, parity, number of data bits, stop bits, and a handshake procedure.

33. Management Information Systems, 3 rd Edition Effy Oz 33 Protocols LAN Protocols –Polling –Contention Usually referred to as Ethernet –Token passing WAN Protocols –OSI (Open Systems Interconnection) Standard protocol model Seven layers

34. Management Information Systems, 3 rd Edition Effy Oz 34 Protocols Figure 6.14 The seven layers of the OSI model

35. Management Information Systems, 3 rd Edition Effy Oz 35 Switching Techniques Circuit Switching –Message is communicated in its entirety from the transmitting computer to the receiving computer Packet Switching –Message is divided into packets of bytes and transmitted via several nodes

36. Management Information Systems, 3 rd Edition Effy Oz 36 A Variety of Services Integrated Services Data Networks (ISDN) Cable Digital Subscriber Line (DSL T1 and T3 Lines Satellite Fixed Wireless Gigabit Ethernet

37. Management Information Systems, 3 rd Edition Effy Oz 37 The Changing Business Environment Cellular phones Videoconferencing Voice Mail Facsimile Web-based Electronic Commerce

38. Management Information Systems, 3 rd Edition Effy Oz 38 Ethical and Societal Issues Telecommuting: Pros and Cons Pros –Saves travel cost and time –Decreases pollution –May reduce unemployment. –Productivity higher among telecommuters

39. Management Information Systems, 3 rd Edition Effy Oz 39 Ethical and Societal Issues Telecommuting: Pros and Cons Cons –Employers tend to pressure telecommuters to work harder than workers in the office. –No office to foster new social ties and camaraderie. –May negatively impact some segments of the economy Restaurants Downtown business and industries