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  1. 1. Discovering Computers 2009 Chapter 9 Communicatio ns and Networks
  2. 2. Chapter 9 Objectives Discuss the components required for successful communications Explain the purpose of communications software Identify various sending and receiving devices Describe various types of lines for communications over the telephone networkDescribe uses of computer communications Describe commonly used communications devices List advantages of using a network Discuss different ways to set up a home network Differentiate among client/server, peer-to-peer, and P2P networks Identify various physical and wireless transmission media Describe the various network communications standards
  3. 3. Communications
  4. 4. CommunicationsWhat are computer___________________? communications Process in which two or more computers or devices transfer data, instructions, and information
  5. 5. Communications What is needed for successful communications? Sending device __________________— Communications Communications channel __________________ initiates instruction to device — connects transmit data, the sending device to media instructions, or the communications on which data, information channel instructions, or information travel Communications Receiving device _________________ device — connects accepts transmission of the communications data, instructions, or channel to the information receiving devicep. 460 - 461
  6. 6. Uses of Computer Communications
  7. 7. Uses of Computer Communications What are some uses of communications technology?p. 462
  8. 8. Uses of Computer Communications What are wireless messaging services? Text messaging Wireless instant allows users to send messaging allows and receive short wireless mobile text messages on a devices to exchange phone or other Picture/video messages mobile device messaging allows users to send graphics, pictures, video clips, sound files, and short text messagesp. 463 - 464
  9. 9. Uses of Computer Communications What are _______________________________ wireless Internet access points  allows wireless connection to Internet in public location  3G and 4G networks  _______________is a Cybercafé coffee house that provides computers with Internet accessp. 464-465 Fig. 9-4
  10. 10. Uses of Computer Communications What is a _____________________________? global positioning system (GPS) 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.p. 466 Fig. 9-6
  11. 11. Uses of Computer Communications  ____________________is working with other users connected Collaboration to a server  Web conference Groupware  _______________is software that allows people work together and share informationp. 467 Fig. 9-7
  12. 12. Uses of Computer Communications  ___________________is voice message converted Voice mail to digital form  _____________________describe standardized Web services software that enables programmers to create applications that communicate with other remote computers over the Internet or on an internal business networkp. 468 Fig. 9-8
  13. 13. Networksp. 469 Fig. 9-9
  14. 14. Networks What is a network?  Collection of computers and devices connected via communications devices and transmission mediap. 469 Fig. 9-9
  15. 15. NetworksNetwork classifications ____________is a network in limited geographical area LAN such as home or office building  Wireless ____________ LAN (WLAN) _____________________________ connects _____s Metropolitan area network (MAN) LA in city or town N _____________________________ a network that Wide area network (WAN) is covers large geographic area using many types of media ____________is world’s largest_________ Internet WAN
  16. 16. Network Network Architectures  _____________: One or more computers act as host Client/Server computer and other computers access the host computer  _______________: Simple network that connects fewer peer-to-peer than 10 computers. Each computer has equal capabilities  _________________________: Enables users to Internet peer-to-peer (P2P) connect to each other’s hard disks and exchange files directly. Sometimes called a file sharing network.p. 472 Fig. 9-13
  17. 17. Network Network Topology: the layout of the computers in a network. 1. _____________: All computers and devices connect to Bus network central cable or busp. 472 Fig. 9-13
  18. 18. Network Network Topology 1. _____________: Cable Ring network forms closed loop (ring), with all computers and devices arranged along ring. Data travels from device to device around entire ring, in one directionp. 472 Fig. 9-13
  19. 19. Network Network Topology 1. _____________: All Star network devices connect to a central device (hub or switch) All data transferred from one computer to another passes through hub or switch.p. 472 Fig. 9-13
  20. 20. Networks What is an___________? intranet Internal network that uses Internet technologies Makes information accessible to employees Typically includes connection to Internet Extranet allows customers or suppliers to access _________ part of company’s intranet __________p. 475
  21. 21. Network Communications Standardsp. 476
  22. 22. Network Communications Standards ___________ technology allows computers to contend Ethernet for access to network. No 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 Token ring _______________ technology controls access to network by requiring devices to pass a special signal, called tokenp. 476
  23. 23. Network Communications Standards _____________________________________________ TCP/IP (Transmission Control Protocol/Internet Protocol) technology transmits data by breaking it up into small pieces, or packets. • Commonly used for Internet transmissions _______________ is a family of standards for 802.11 (Wi-Fi) wireless LANsp. 476
  24. 24. Network Communications Standards ___________ Short-range radio waves transmit Bluetooth data between Bluetooth devices • Contains a small chip to communicate with each other. _______ is a specification allows data to be WAB transferred wirelessly via short-range radio waves. _______ specification allows data to be transferred IrDA wirelessly via infrared light waves.p. 476
  25. 25. Network Communications Standards ___________ uses radio signals to communicate RFID with a tag placed in an object • Radio Frequency Identification. _______ is a standard that specifies how wireless WiMAX devices communicate over the air in a wide area. • Worldwide Interoperability for Microwave Access _______ allow wireless mobile devices WAP to access Internet. • Wireless Application Protocol • Use client/server network.p. 476
  26. 26. Communications Software
  27. 27. Communications Software What is communications software?  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 anotherp. 480
  28. 28. Communications Over the Telephone Networkp. 481 Fig. 9-23
  29. 29. Communications Over the Telephone Network  _______________________________________________: public switched telephone network (PSTN) 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.p. 481 Fig. 9-23
  30. 30. Communications Over the Telephone Network Various lines that use the telephone network for data communications 1. _______________ Temporary connection using dial-up line 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 1. _______________ Always-on connection between Dedicated line two communications devices  There are five types of lines.p. 481
  31. 31. Communications Over the Telephone Network Dedicated lines  _______________ Integrated Services Digital ISDN lines Network. Require both ends of the connection have ________ ISDN modem.  __________Digital Subscriber Line DSL For the small business or home user  __________Fiber to the Premises FTTP Use fiber-optic cable to provide extremely high- speed Internet accessp. 481
  32. 32. Communications Over the Telephone Network Dedicated lines  _______________ Long-distance digital telephone T-Carrier lines lines that carry multiple signals over a single communications line. T1 line is most popular.  __________ Asynchronous Transfer Mode ATM Very high speed. Large amounts of traffic use this.p. 481
  33. 33. Communications Devicesp. 484
  34. 34. Communications Devices _________________ Dial-up modem  Converts digital signals to analog signals and vice versa  Usually in the form of an adapter cardp. 485
  35. 35. Communications Devices What are____________________ ? ISDN and DSL modems 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 unitp. 485
  36. 36. Communications Devices What is a_____________? cable modem  Sends and receives data over cable television network  Much faster than dial-up modem or ISDN  Sometimes called a broadband modemp. 484 - 486 Fig. 9-28
  37. 37. Communications DevicesWhat is a________________? wireless modem 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
  38. 38. Communications Devices What is a______________? network card  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)p. 486 - 487 Fig. 9-30
  39. 39. Communications Devices What is a_____________________? wireless access point  Central communications device that allows computers and devices to transfer data wirelessly among themselves or wirelessly to a wired networkp. 487 Fig. 9-31
  40. 40. Communications DevicesWhat is a____________? router 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. 41. Communications DevicesWhat is a_______________? hub or switch Device that provides central point for cables in network
  42. 42. Home NetworksWhat 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. 43. Communications Channel
  44. 44. Communications ChannelWhat is a communications channel? Transmission media on which data travels in communications system Transmission media are materials or substances capable of carrying one or more Bandwidth is amount of signals data that can travel over a communications channel
  45. 45. Physical Transmission Media What is physical transmission media?  Wire, cable, and other tangible materials used to send communications signalsp. 492 Fig. 9-36
  46. 46. Physical Transmission Media  Twisted-pair ______________cable consists of one or more twisted-pair wires bundled together. It is used for telephone systems and network cabling  Coaxial _________cable consists of a single copper wire. It is often used for cable television wiringp. 493 Fig. 9-37—9-38
  47. 47. Physical Transmission MediaWhat is __________cable? fiber-optic 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. 48. Wireless Transmission Media What is wireless transmission media?  Used when inconvenient, impractical, or impossible to install cables  Includes Bluetooth and IrDAp. 494 Fig. 9-40
  49. 49. Wireless Transmission Media ________________ Broadcast radio distributes radio signals over long and short distances ________________ Cellular radio is form of ________________ broadcast radio used for mobile communications
  50. 50. Wireless Transmission MediaWhat is a __________station? microwave Earth-based reflective dish used for microwave communications Must transmit in straight line with no obstructions
  51. 51. Wireless Transmission MediaWhat is a_______________________? communications satellite Space station that receives microwave signals from earth-based station, amplifies signals, and broadcasts signals back to any number of earth-based stations
  52. 52. Summary of Communications and Networks Communications terminology and applications Various communications devices, media, and procedures How to join computers into a networkChapter 9 Complete