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Chapter 6 Information Technology in Business: Telecommunications and Networks. Learning Objectives. When you finish this chapter, you will: Recognize why successful managers must be familiar with telecommunications concepts and terminology.
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Chapter 6Information Technology in Business: Telecommunications and Networks Management Information Systems, 3rd Edition Effy Oz
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. Management Information Systems, 3rd Edition Effy Oz
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. Management Information Systems, 3rd Edition Effy Oz
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 Management Information Systems, 3rd Edition Effy Oz
Data Communications • Data Communications • Any transfer of data within a computer, between a computer and another device, or between two computers Management Information Systems, 3rd Edition Effy Oz
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 Management Information Systems, 3rd Edition Effy Oz
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 Management Information Systems, 3rd Edition Effy Oz
Figure 6.2 Simplex, half-duplex, and full-duplex communication Communication Direction Management Information Systems, 3rd Edition Effy Oz
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 Management Information Systems, 3rd Edition Effy Oz
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. Management Information Systems, 3rd Edition Effy Oz
Figure 6.4 Synchronous transmission Communication Modes Management Information Systems, 3rd Edition Effy Oz
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 Management Information Systems, 3rd Edition Effy Oz
Figure 6.5 Transmission speed measurement unit Channels and Media Management Information Systems, 3rd Edition Effy Oz
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. Management Information Systems, 3rd Edition Effy Oz
Figure 6.6 Telecommunications transmission speeds of different media Channels and Media Management Information Systems, 3rd Edition Effy Oz
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 Management Information Systems, 3rd Edition Effy Oz
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. Management Information Systems, 3rd Edition Effy Oz
Figure 6.7 Characteristics of channel media Channels and Media Management Information Systems, 3rd Edition Effy Oz
Modulation • Analog vs. Digital • Analog signals • A continuous series of waves • Digital signals • A series of discrete bits Management Information Systems, 3rd Edition Effy Oz
Modulation • Modulation • Modification of a digital signal into an analog signal • Demodulation • Modification of an analog signal into a digital signal Management Information Systems, 3rd Edition Effy Oz
Figure 6.8 Signal modulation Modulation Management Information Systems, 3rd Edition Effy Oz
Modulation • Amplitude Modulation (AM) • Frequency Modulation (FM) • Phase Modulation Management Information Systems, 3rd Edition Effy Oz
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 Management Information Systems, 3rd Edition Effy Oz
Figure 6.9 Multiplexing Modulation Management Information Systems, 3rd Edition Effy Oz
Figure 6.10 Frequency division Modulation Management Information Systems, 3rd Edition Effy Oz
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 Management Information Systems, 3rd Edition Effy Oz
Figure 6.11 Where wireless LANs are a good choice Networks Management Information Systems, 3rd Edition Effy Oz
Networks • Network Topology • Physical layout of the nodes in a network • Star • Ring • Bus • Tree Management Information Systems, 3rd Edition Effy Oz
Figure 6.12 Network topologies Network Topology Management Information Systems, 3rd Edition Effy Oz
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) Management Information Systems, 3rd Edition Effy Oz
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 Management Information Systems, 3rd Edition Effy Oz
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. Protocols Management Information Systems, 3rd Edition Effy Oz
Protocols • LAN Protocols • Polling • Contention • Usually referred to as Ethernet • Token passing • WAN Protocols • OSI (Open Systems Interconnection) • Standard protocol model • Seven layers Management Information Systems, 3rd Edition Effy Oz
Figure 6.14 The seven layers of the OSI model Protocols Management Information Systems, 3rd Edition Effy Oz
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 Management Information Systems, 3rd Edition Effy Oz
A Variety of Services • Integrated Services Data Networks (ISDN) • Cable • Digital Subscriber Line (DSL • T1 and T3 Lines • Satellite • Fixed Wireless • Gigabit Ethernet Management Information Systems, 3rd Edition Effy Oz
The Changing Business Environment • Cellular phones • Videoconferencing • Voice Mail • Facsimile • Web-based Electronic Commerce Management Information Systems, 3rd Edition Effy Oz
Ethical and Societal IssuesTelecommuting: Pros and Cons • Pros • Saves travel cost and time • Decreases pollution • May reduce unemployment. • Productivity higher among telecommuters Management Information Systems, 3rd Edition Effy Oz
Ethical and Societal IssuesTelecommuting: 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 Management Information Systems, 3rd Edition Effy Oz