Transcript Management Information Systems

Chapter 6
Information Technology in
Business: Telecommunications
and Networks
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Learning Objectives
• Explain why successful managers must be familiar
with telecommunications concepts and
terminology
• Describe the principles of communication within a
computer system and among computers
• Identify the major media and devices used in
telecommunications
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Learning Objectives (Cont.)
• List and explain the functions of different network
layouts and the concept of protocols
• Explain how telecommunications can improve
operations in organizations
• Cite the latest developments in telecommunications
media and transmission speed
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Telecommunications in Business
• 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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Telecommunications in Daily Use
• Cellular Phones
• Videoconferences
• Voice Mail
• Facsimile
• Information Kiosks
• Pay at the Pump
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Telecommunications in Daily Use
(Cont.)
• Easy Passing
• Web-Based Electronic Commerce
• Worldwide Peer-to-Peer File Sharing
– Napster, Gnutella, BearShare, Morpheus
– With directory
– Without directory
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Telecommunications in Daily Use
(Cont.)
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Data Communications
• Any transfer of data within a computer, between a
computer and another device, or between two
computers
• Parallel and Serial Data Communications
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Data Communications (Cont.)
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Communication Direction
• 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 Direction (Cont.)
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Error Detection
• Parity Check
– Error detection method
– Checks that no bits are added or deleted during
transmission
– Odd Parity Check looks for an odd number of ones
– Even Parity Check looks for even number of ones
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Bandwidth and Media
• Communications medium
– Physical medium through which data can be
communicated
– Telephone lines, television cables
• Capacity
– Speed at which data are communicated
– Also called the transmission rate
– It is often called “bandwidth”
• Bandwidth is measured in bits per second (bps)
– The greater the capacity, the faster the transmission
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Bandwidth and Media (Cont.)
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Bandwidth and Media (Cont.)
• Bandwidth
– Narrowband is low speed
– Broadband has greater capacity
• Media
– A medium is any means by which data can be
transmitted
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Transmission speed
• A medium’s capacity is determined by the range of
bits per second at which it can operate
• Baud is the number of signals per minute
• Repeater receives and strengthens signals before
sending them on
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Transmission Speed (Cont.)
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Twisted Pair
• Telephone line made of a pair of copper wires
twisted to reduce electromagnetic interference
(EMI)
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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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Microwaves
• High-frequency, short radio-frequency (RF) waves
– Terrestrial microwave
– Satellite microwave
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Optical Fiber
• Fiber-optic technology uses light instead of
electricity to transmit data
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Characteristics of Media
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Modulation
• Modification of a digital signal into an analog
signal
• Demodulation
– Modification of an analog signal into a digital
signal
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Modulation (Cont.)
• Analog vs. Digital
– Analog: A continuous series of waves
– Digital: A series of discrete bits
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Modulation (Cont.)
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Modulation (Cont.)
• Amplitude Modulation (AM)
• Frequency Modulation (FM)
• Phase Modulation
• Modems
– Devices that modulate and demodulate signals
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Modulation (Cont.)
Figure 6.9 Multiplexing
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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
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Network Topology
• Physical layout of the nodes in a network
– Star
– Ring
– Bus
– Tree
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Network Topology
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Networking Hardware
• Network Interface Card
• Hub
• Switch
• Bridge
• Router
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Virtual Private Network
• A combination of private and public lines
• A link between a private network and the Internet
• “Virtual” refers to the illusion that the use is
accessing a private network directly
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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
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Protocols (Cont.)
• LAN Protocols
– Polling
– Contention
– Token passing
• WAN Protocols
– OSI (Open Systems Interconnection)
• Standard protocol model
• Seven layers
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Protocols (Cont.)
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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
– TCP/IP
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Switching Techniques (Cont.)
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The Changing Business
Environment
• Cellular Phones
• Teleconferencing
• Voice Mail
• Facsimile
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A Variety of Services
• Cable
• Digital Subscriber Line (DSL)
• T1 and T3 Lines
• Satellite
• Fixed Wireless
• Gigabit Ethernet
• Optical Carrier
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A Variety of Services (Cont.)
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A Wireless Revolution
• Popular Wireless Technologies
• Would You Like Wi-Fi With That?
• Combining Technologies
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Wireless Technologies (Cont.)
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Wireless Technologies (Cont.)
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Ethical and Societal Issues
Telecommuting: Pros and Cons
• Pros
– Saves travel cost and time
– Decreases pollution
– May reduce unemployment.
– Productivity higher among telecommuters
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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
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Summary
• Telecommunications concepts and terminology
• Communication within a computer system and
among computers
• Telecommunications media and devices
• Network layouts and protocols
• Telecommunications impact on operations
• Telecommunications developments and speed
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