Information Technology in Business: Telecommunications and Networks

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Chapter 6

• Information Technology in Business
  Telecommunications and Networks

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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.

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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.
  

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Telecommunications in Business

• 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 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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Parallel/Serial Communication
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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

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Communication Mode

• 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 Modes
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Communication 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 Modes
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Channels and Media

• Communication Channel
• Physical medium through which data can be
  communicated.
• Channel Capacity
• Narrow band
• Broadband

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Channels and Media
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Channels and Media

• Media
• A medium is any means by which data can be
  transmitted.
• Transmission speed
• A mediums capacity is determined by the range of
  bits per second at which it can operate.
• Baud
• Repeater

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Channels and Media
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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

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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.

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Channels and Media
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Modulation

• Analog 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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Modulation

• Amplitude Modulation (AM)
• Frequency Modulation (FM)
• Phase Modulation

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Modulation
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Modulation

• 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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Multiplexing
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Frequency Devision
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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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Networks

• Network Topology
• Physical layout of the nodes in a network
• Star
• Ring
• Bus
• Tree

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Network Topology
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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
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Protocols

• LAN Protocols
• Polling
• Contention
• Token passing
• WAN Protocols
• OSI (Open Systems Interconnection)
• Standard protocol model
• Seven layers

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Protocols
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Switching Techniques and Transfer 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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The Changing Business Environment

• Cellular Phones
• Teleconferencing
• Voice Mail
• Facsimile

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Ethical and Societal IssuesTelecommuting Pros

• Saves travel cost and time.
• Decreases pollution.
• May reduce unemployment.
• Productivity higher among telecommuters.

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ETHICS AND SOCIETYTelecommuting 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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