Information Technology in Business: Telecommunications and Networks

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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
• Serial data transfer refers to transmitting data
  one bit at a time.
• Parallel means the device is capable of receiving
  more than one bit at a time (that is, it receives
  several bits in parallel). Most modern printers
  are parallel.

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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

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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 mediums capacity is determined by the range of
  bits per second at which it can operate
• Baud is the number of signals per minute
• e.g. 300 bits per second 300 baud
• 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
• SUPER CLEAR GLASS STRANDS
• FAST, LIGHT, DURABLE
• TRILLIONS OF BITS PER SECOND, FULL DUPLEX
• EXPENSIVE, HARDER TO INSTALL
• OFTEN USED AS BACKBONE OF NETWORKS

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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
• Modems
• Devices that modulate and demodulate signals
• Multiplexor - device that transmits multiple
  signals over single medium

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Modulation (Cont.)

• Analog vs. Digital
• Analog A continuous series of waves
• Digital A series of discrete bits

00101110100111010010101011101111001000100001011110
10110100111010010010110010101101100
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Modulation (Cont.)
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Modulation (Cont.)
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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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Star Topology
Star topology a central host computer receives
all messages and then forwards the message to the
appropriate computer or device (e.g. printer) on
the network. In a star topology, all
communications must go through the main computer,
and this topology is one of the oldest types.
Advantage easy to expand the network by adding
more computers. This set-up is ideal when some
information has to be centralized on the host
computer, and other computers on the network can
download that information from the host computer.

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Bus Topology

• A bus topology connects all computers on the
  network through a single circuit such as fiber
  optics, twisted pair etc to a central channel.
  Signals transmitted over the channel are called
  messages. This topology transmits each message to
  all computers on the network, although only the
  targeted device will respond to the message. Each
  device has an address and each device forwards
  messages to the address of a given device.
• Advantages
• easy to add or remove devices from the network
  without affecting network performance.
• if one of the devices on the network fails, the
  network is not affected.
• Disadvantage network performance decreases as
  the number of messages increases, because each
  device checks to see if the message is for it, or
  for some other device. This topology is ideal for
  LANs and for applications such as e-mail and
  file transfers.

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Ring Topology

• Ring Topology network devices are connected to
  one another in the shape of a closed loop, so
  that each device is connected directly to two
  other devices, one on either side of it (closed
  ring). This topology transmits a message to all
  devices between the sending node and the
  receiving node. Each computer communicates
  directly with any other computer by specifying
  the address of the device the topology
  distributes processing and control functions
  among all devices on the network. If a computer
  on the network fails, the message is rerouted
  around it.

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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 IssuesTelecommuting 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 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

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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