management information systems, 4 th edition 1 chapter 6 information technology in business:...

Management Information Systems, 4th Edition 1

Chapter 6Information Technology in

Business: Telecommunications and Networks


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


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


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


Telecommunications in Daily Use

• Cellular Phones

• Videoconferences

• Voice Mail

• Facsimile

• Information Kiosks

• Pay at the Pump


• Easy Passing

• Web-Based Electronic Commerce

• Worldwide Peer-to-Peer File Sharing

– Napster, Gnutella, BearShare, Morpheus

– With directory

– Without directory

Telecommunications in Daily Use (Cont.)


Telecommunications in Daily Use (Cont.)


Data Communications

• Any transfer of data within a computer, between a computer and another device, or between two computers

• Parallel and Serial Data Communications


Data Communications (Cont.)


• Simplex

– One-way in one direction

• Half-Duplex

– One-way in two directions

• Full-Duplex

– Two-way in two directions

Communication Direction


Communication Direction (Cont.)


• 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


• 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


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

Bandwidth and Media (Cont.)


• 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


Transmission Speed (Cont.)


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

Twisted Pair


Coaxial Cable

• Commonly used for cable television transmission

– More expensive than twisted pair

– Greater transmission rate than twisted pair

– Much less susceptible to EMI


• High-frequency, short radio-frequency (RF) waves

– Terrestrial microwave

– Satellite microwave

Microwaves


Optical Fiber

• Fiber-optic technology uses light instead of electricity to transmit data


Characteristics of Media


Modulation

• Modification of a digital signal into an analog signal

• Demodulation

– Modification of an analog signal into a digital signal


• Analog vs. Digital

– Analog: A continuous series of waves

– Digital: A series of discrete bits

Modulation (Cont.)


Modulation (Cont.)


Modulation (Cont.)

• Amplitude Modulation (AM)

• Frequency Modulation (FM)

• Phase Modulation

• Modems

– Devices that modulate and demodulate signals


Modulation (Cont.)

Figure 6.9 Multiplexing


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


Network Topology

• Physical layout of the nodes in a network

– Star

– Ring

– Bus

– Tree


Network Topology


Networking Hardware

• Network Interface Card

• Hub

• Switch

• Bridge

• Router


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


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


Protocols (Cont.)

• LAN Protocols– Polling

– Contention

– Token passing

• WAN Protocols– OSI (Open Systems Interconnection)

• Standard protocol model

• Seven layers


Protocols (Cont.)


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


Switching Techniques (Cont.)


The Changing Business Environment

• Cellular Phones

• Teleconferencing

• Voice Mail

• Facsimile


A Variety of Services• Cable

• Digital Subscriber Line (DSL)

• T1 and T3 Lines

• Satellite

• Fixed Wireless

• Gigabit Ethernet

• Optical Carrier


A Variety of Services (Cont.)


A Wireless Revolution

• Popular Wireless Technologies

• Would You Like Wi-Fi With That?

• Combining Technologies


Wireless Technologies (Cont.)


Ethical and Societal IssuesTelecommuting: Pros and Cons

• Pros

– Saves travel cost and time

– Decreases pollution

– May reduce unemployment.

– Productivity higher among telecommuters


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


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

management information systems, 4 th edition 1 chapter 6 information technology in business:...

Documents

media cont

daily use cont

digital signalmodulation

ontransmission speed

telecommunications media

businesstransmittal

bandwidth bandwidth

major media