chapter 6 information technology in business: telecommunications and networks
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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. - PowerPoint PPT PresentationTRANSCRIPT
6Management Information Systems, Second EditionEffy Oz
Chapter 6Chapter 6Information Technology Information Technology in Business: in Business: Telecommunications and Telecommunications and NetworksNetworks
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Learning ObjectivesLearning ObjectivesWhen 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.
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Learning ObjectivesLearning 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.
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Telecommunications in Telecommunications in BusinessBusiness
Telecommunications Transmittal of data from one computer to
another over a distance
Telecommunications has improved business in three main ways: Better communication Higher efficiency Better distribution of data
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What is Data What is Data Communications?Communications?
Data Communications
Any transfer of data within a computer, between a computer and another device, or between two computers
Two Basic Modes Parallel transmission Serial transmission
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What is Data What is Data Communications?Communications?
Figure 6.1 Parallel and serial transmission
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Communication DirectionCommunication 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
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Communication DirectionCommunication Direction
Figure 6.2 Simplex, half-duplex, and full-duplex communication
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Communication DirectionCommunication Direction
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
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Communication ModesCommunication Modes
Figure 6.3 The character D transmitted in asynchronous mode
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Communication ModesCommunication Modes
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.
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Communication ModesCommunication Modes
Figure 6.4 Synchronous transmission
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Channels and MediaChannels and Media
Communication Channel Physical medium through which data can
be communicated.
Channel Capacity Narrow band Broadband
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Channels and MediaChannels and Media
Figure 6.5 Transmission speed measurement unit
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Channels and MediaChannels 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. Baud Repeater
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Channels and MediaChannels and Media
Figure 6.6 Telecommunications transmission speeds of different media
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Channels and MediaChannels 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
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Channels and MediaChannels 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.
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Channels and MediaChannels and Media
Figure 6.7 Characteristics of channel media
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ModulationModulationAnalog vs. Digital
Analog signals A continuous series of waves
Digital signals A series of discrete bits
Modulation Modification of a digital signal into an analog signal
Demodulation Modification of an analog signal into a digital signal
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ModulationModulation
Figure 6.8 Signal modulation
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ModulationModulation
Amplitude Modulation (AM)
Frequency Modulation (FM)
Phase Modulation
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ModulationModulation
Modems Devices that modulate and demodulate
signals
Multiplexers Devices that allow several telephones or
computers to transmit data through a single line Frequency division multiplexing Time-division multiplexing
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ModulationModulation
Figure 6.9 Multiplexing
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ModulationModulation
Figure 6.10 Frequency division
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NetworksNetworks
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
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NetworksNetworks
Figure 6.11 Where wireless LANs are a good choice
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NetworksNetworks
Network Topology Physical layout of the nodes in a network
Star
Ring
Bus
Tree
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Network TopologyNetwork Topology
Figure 6.12 Network topologies
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ProtocolsProtocols
Communication protocols
Rules governing the communication between computers or between computers and other computer-related devices
Network protocols
Rules governing a network of devices
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ProtocolsProtocols
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.
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ProtocolsProtocols
LAN Protocols Polling Contention Token passing
WAN Protocols OSI (Open Systems Interconnection)
Standard protocol model Seven layers
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ProtocolsProtocols
Figure 6.14 The seven layers of the OSI model
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Switching Techniques and Switching Techniques and Transfer ModesTransfer Modes
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
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A Variety of ServicesA Variety of Services
Figure 6.15Services offered by telecommunicationsfirms
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The Changing Business The Changing Business EnvironmentEnvironment
Cellular Phones
Teleconferencing
Voice Mail
Facsimile
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Ethical and Societal IssuesEthical and Societal IssuesTelecommuting: Pros and ConsTelecommuting: Pros and Cons
Pros
Saves travel cost and time.
Decreases pollution.
May reduce unemployment.
Productivity higher among telecommuters.
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ETHICS AND SOCIETYETHICS AND SOCIETYTelecommuting: Pros and ConsTelecommuting: 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