Chap06 Telecommunications and Networks

Management Information Systems, 4th Edition
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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/Fax
•Information Kiosks
•Pay at the Pump

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•Easy Passing
•Web-Based Electronic Commerce
•Worldwide Peer-to-Peer File Sharing
–With directory
–Without directory
Telecommunications in Daily Use (Cont.)

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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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•Simplex
–One-way in one direction
•Half-Duplex
–One-way in two directions
•Full-Duplex
–Two-way in two directions
Communication Direction

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Communication Direction (Cont.)

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•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
Error Detection

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•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
Bandwidth and Media

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Bandwidth and Media (Cont.)

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•Bandwidth
–Narrowband is low speed
–Broadband has greater capacity
•Media
–A medium is any means by which data can be transmitted
Bandwidth and Media (Cont.)

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•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
Transmission speed

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Transmission Speed (Cont.)

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•Telephone line made of a pair of copper wires twisted to reduce electromagnetic interference (EMI)
Twisted Pair

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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 (Electronic Magnetic Interference )

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•High-frequency, short radio-frequency (RF) waves
–Terrestrial microwave
–Satellite microwave
Microwaves

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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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•Analog vs. Digital
–Analog: A continuous series of waves
–Digital: A series of discrete bits
Modulation (Cont.)

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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 (connect different networks)
•Router ("traffic directing" functions on the Internet)

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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
•https://vpn2.stut.edu.tw

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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

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Switching Techniques
•Circuit Switching
–Message is communicated in its entirety from the transmitting computers to the receiving computers
•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/Fax
•What else in mobile device?

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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 Wireless Revolution
•Popular Wireless Technologies
•Would You Like Wi-Fi?
•Combining Technologies

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Wireless Technologies (Cont.)

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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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