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Discovering Computers 2009
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Discovering Computers 2009


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  • 1. Chapter 9 Communications and Networks
  • 2. Chapter 9 Objectives Discuss the components required for successful communications Identify various sending and receiving devices Describe uses of computer communications List advantages of using a network Differentiate among client/server, peer-to-peer, and P2P networks Describe the various network communications standards Explain the purpose of communications software Describe various types of lines for communications over the telephone network Describe commonly used communications devices Discuss different ways to set up a home network Identify various physical and wireless transmission media
  • 3. Communications
  • 4. Communications
    • What are computer ___________________ ?
      • Process in which two or more computers or devices transfer data, instructions, and information
  • 5.
    • What is needed for successful communications?
    Communications p. 460 - 461 Sending device Communications channel Receiving d evice __________________ — initiates instruction to transmit data, instructions, or information Communications device — connects the communications channel to the receiving device _________________ accepts transmission of data, instructions, or information Communications device — connects the sending device to the communications channel __________________ media on which data, instructions, or information travel
  • 6. Uses of Computer Communications
  • 7. Uses of Computer Communications
    • What are some uses of communications technology?
    p. 462
  • 8. Uses of Computer Communications
    • What are wireless messaging services?
    p. 463 - 464 Wireless instant messaging allows wireless mobile devices to exchange messages Text messaging allows users to send and receive short text messages on a phone or other mobile device Picture/video messaging allows users to send graphics, pictures, video clips, sound files, and short text messages
  • 9. Uses of Computer Communications
    • What are _______________________________
    p. 464-465 Fig. 9-4
      • allows wireless connection to Internet in public location
        • 3G and 4G networks
      • _______________ is a coffee house that provides computers with Internet access
    wireless Internet access points Cybercafé
  • 10. Uses of Computer Communications
    • What is a _____________________________?
    p. 466 Fig. 9-6 A navigation system that consists of one or more earth-based receivers that accept and analyze signals sent by satellites in order to determine the receiver’s geographic location. global positioning system (GPS)
  • 11. Uses of Computer Communications p. 467 Fig. 9-7
      • _______________ is software that allows people work together and share i nformation
      • ____________________ is working with other users connected to a server
        • Web conference
    Collaboration Groupware
  • 12. Uses of Computer Communications p. 468 Fig. 9-8
      • ___________________ is voice message converted to digital form
      • _____________________ describe standardized software that enables programmers to create applications that communicate with other remote computers over the Internet or on an internal business network
    Voice mail Web services
  • 13. Networks p. 469 Fig. 9-9
  • 14. Networks
    • What is a network ?
    p. 469 Fig. 9-9
      • Collection of computers and devices connected via communications devices and transmission media
  • 15. Networks
    • Network classifications
      • ____________ is a network in limited geographical area such as home or office building
        • Wireless ____________
      • _____________________________ connects _____ s in city or town
      • _____________________________
    LAN LAN (WLAN) Metropolitan area network (MAN) LAN is a n etwork that covers large geographic area using many types of media W ide area network (WAN)
      • ____________ is world’s largest _________
    WAN Internet
  • 16. Network p. 472 Fig. 9-13
      • _____________: One or more computers act as host computer and other computers access the host computer
      • _______________: Simple network that connects fewer than 10 computers . Each computer has equal capabilities
      • _________________________: Enables users to connect to each other’s hard disks and exchange files directly . Sometimes called a file sharing network .
    Network Architectures Client/Server peer-to-peer Internet peer-to-peer (P2P)
  • 17. Network p. 472 Fig. 9-13
      • _____________: All computers and devices connect to central cable or bus
    Network Topology: the layout of the computers in a network. Bus network
  • 18. Network p. 472 Fig. 9-13
      • _____________: Cable forms closed loop (ring), with all computers and devices arranged along ring .
      • Data travels from device to device around entire ring, in one direction
    Network Topology Ring network
  • 19. Network p. 472 Fig. 9-13
      • _____________: All devices connect to a central device (hub or switch)
      • All data transferred from one computer to another passes through hub or switch .
    Network Topology Star network
  • 20. Networks
    • What is an ___________ ?
    p. 475 intranet Extranet intranet _________ allows customers or suppliers to access part of company’s __________ Typically includes connection to Internet Makes information accessible to employees Internal network that uses Internet technologies
  • 21. Network Communications Standards p. 476
  • 22. Network Communications Standards p. 476
    • ___________ technology allows computers to contend for access to network .
    • N o controlling computers or devices.
      • If two computers send data at same time, a collision occurs and computers must send again
      • Bus topology, but sometimes star topology
    _______________ technology controls access to network by requiring devices to pass a special signal, called token Ethernet Token ring
  • 23. Network Communications Standards p. 476
    • _____________________________________________
      • technology transmits data by breaking it up into
      • small pieces, or packets .
        • Commonly used for Internet transmissions
    _______________ is a family of standards for wireless LANs TCP/IP ( T ransmission C ontrol P rotocol/ I nternet P rotocol) 802.11 ( Wi-Fi )
  • 24. Network Communications Standards p. 476
    • ___________ Short-range radio waves transmit data between Bluetooth devices
      • Contains a small chip to communicate with each other.
    _______ is a specification allows data to be transferred wirelessly via short-range radio waves . Bluetooth WAB _______ specification allows data to be transferred wirelessly via infrared light waves . IrDA
  • 25. Network Communications Standards p. 476
    • ___________ uses radio signals to communicate with a tag placed in an object
      • Radio Frequency Identification .
    • _______ is a standard that specifies how wireless devices communicate over the air in a wide area .
      • Worldwide Interoperability for Microwave Access
    • _______ allow wireless mobile devices to access Internet .
      • Wireless Application Protocol
      • Use client/server network.
  • 26. Communications Software
  • 27. Communications Software
    • What is communications software ?
    p. 480
    • Programs that help users establish connection to Internet, other network, or another computer
    • Programs that help users manage transmission of data, instructions, and information
    • Programs that provide an interface for users to communicate with one a nother
  • 28. Communications Over the Telephone Network p. 481 Fig. 9-23
  • 29. Communications Over the Telephone Network p. 481 Fig. 9-23
      • _______________________________________________:
      • Worldwide telephone system that handles voice-oriented telephone calls .
      • The entire telephone network uses digital technology.
      • But, the final link from the local telephone company to a home often uses analog.
    public switched telephone network (PSTN)
  • 30. Communications Over the Telephone Network
    • Various lines that use the telephone network for data communications
    p. 481
      • _______________ Temporary connection using telephone line for communications
        • Costs no more than making regular call
        • Computers at any two locations can establish a connection using modems and telephone network
    dial-up line
      • _______________ Always-on connection between two communications devices
        • There are five types of lines.
    Dedicated line
  • 31. Communications Over the Telephone Network
    • Dedicated lines
    p. 481
      • _______________ Integrated Services Digital Network.
        • Require both ends of the connection have ________ modem.
    ISDN line s ISDN
      • __________Digital Subscriber Line
        • For the small business or home user
      • __________Fiber to the Premises
        • Use fiber-optic cable to provide extremely high-speed Internet access
  • 32. Communications Over the Telephone Network
    • Dedicated lines
    p. 481
      • _______________ Long-distance digital telephone lines that carry multiple signals over a single communications line.
        • T1 line is most popular.
    T-Carrier line s
      • __________ Asynchronous Transfer Mode
        • Very high speed.
        • Large amounts of traffic use this.
  • 33. Communications Devices p. 484
  • 34. Communications Devices
    • _________________
    p. 485
      • C onverts digital signals to analog signals and vice versa
        • Usually in the form of an adapter card
    D ial-up modem
  • 35. Communications Devices
    • What are ____________________ ?
    p. 485 Communications devices that send and receive digital ISDN and DSL signals Usually external devices in which one end connects to a telephone line and the other end connects to a port on the system unit ISDN and DSL modems
  • 36. Communications Devices
    • What is a _____________ ?
    p. 484 - 486 Fig. 9-28
      • Sends and receives data over cable television network
      • Much faster than dial-up modem or ISDN
      • Sometimes called a broadband modem
    cable modem
  • 37. Communications Devices
    • What is a ________________ ?
      • Allows access to the Web wirelessly from a notebook computer, a smart phone, or other mobile device
      • Typically use the same waves used by cellular telephones
    wireless modem
  • 38. Communications Devices
    • What is a ______________ ?
    p. 486 - 487 Fig. 9-30
      • Adapter card, PC Card, ExpressCard module, USB network adapter, or flash card that enables computer or device to access network
      • Sometimes called network interface card (NIC)
    network card
  • 39. Communications Devices
    • What is a _____________________ ?
    p. 487 Fig. 9-31
      • Central communications device that allows computers and devices to transfer data wirelessly among themselves or wirelessly to a wired network
    wireless access point
  • 40. Communications Devices
    • What is a ____________ ?
      • Connects computers and transmits data to correct destination on network
      • Routers forward data on Internet using fastest available path
      • Some routers have a built-in hardware firewall
  • 41. Communications Devices
    • What is a _______________ ?
      • Device that provides central point for cables in network
    hub or switch
  • 42. Home Networks
    • What is a home network ?
      • Multiple computers connected in home
      • Several types of home networks
        • Ethernet — connect computers via cable
        • Powerline cable — use electrical lines in house
        • Phoneline — use telephone lines
  • 43. Communications Channel
  • 44. Communications Channel
    • What is a communications channel ?
      • Transmission media on which data travels in communications system
      • Bandwidth is amount of data that can travel over a communications channel
      • Transmission media are materials or substances capable of carrying one or more signals
  • 45. Physical Transmission Media
    • What is physical transmission media?
    p. 492 Fig. 9-36
      • Wire, cable, and other tangible materials used to send communications signals
  • 46. Physical Transmission Media p. 493 Fig. 9-37—9-38
      • ______________ cable consists of one or more twisted-pair wires bundled together. It is used for telephone systems and network cabling
      • _________ cable consists of a single copper wire. It is often used for cable television wiring
    Twisted-pair Coaxial
  • 47. Physical Transmission Media
    • What is __________ cable ?
      • Consists of dozens or hundreds of thin strands of glass or plastic
      • Capable of carrying significantly more data at faster speeds than wire cables
      • Less susceptible to interference (noise) and, therefore, more secure
  • 48. Wireless Transmission Media
    • What is wireless transmission media ?
    p. 494 Fig. 9-40
      • Used when inconvenient, impractical, or impossible to install cables
      • Includes Bluetooth and IrDA
  • 49. Wireless Transmission Media
      • ________________ distributes radio signals over long and short distances
      • ________________ is form of ________________ used for mobile communications
    Broadcast radio Cellular radio broadcast radio
  • 50. Wireless Transmission Media
    • What is a __________ station?
      • Earth-based reflective dish used for microwave communications
      • Must transmit in straight line with no obstructions
  • 51. Wireless Transmission Media
    • What is a _______________________ ?
      • Space station that receives microwave signals from earth-based station, amplifies signals, and broadcasts signals back to any number of earth-based stations
    communications satellite
  • 52. Summary of Communications and Networks Chapter 9 Complete Communications terminology and applications How to join computers into a network Various communications devices, media, and procedures