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Chapter 9 Communications and Networks

Chapter 9 Communications and Networks. Chapter 9 Objectives. Discuss the components required for successful communications. Explain the purpose of communications software. Identify various sending and receiving devices.

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Chapter 9 Communications and Networks

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  1. Chapter 9 Communications and Networks

  2. Chapter 9 Objectives Discuss the components required for successful communications Explain the purpose ofcommunications software Identify various sendingand receiving devices Describe various types of lines for communications over the telephone network Describe uses of computer communications Describe commonly usedcommunications devices List advantages of using a network Discuss different ways to set upa 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. Communications

  4. Communications communications What are computer___________________? • Process in which two or more computers or devices transfer data, instructions, and information

  5. Communications __________________— initiates instruction to transmit data, instructions, or information Communications device— connects the sending device to the communications channel __________________ media on which data, instructions, or information travel Communications device— connects the communications channel to the receiving device _________________ accepts transmission of data, instructions, or information What is needed for successful communications? Sending device Communications channel Receiving device p. 460 - 461

  6. Uses of Computer Communications

  7. Uses of Computer Communications What are some uses of communications technology? p. 462

  8. Uses of Computer Communications Text messagingallows 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 Wireless instant messagingallows wireless mobile devices to exchange messages What are wireless messaging services? p. 463 - 464

  9. Uses of Computer Communications wireless Internet access points What are _______________________________ • allows wireless connection to Internet in public location • 3G and 4G networks • _______________is a coffee house that provides computers with Internet access Cybercafé p. 464-465 Fig. 9-4

  10. Uses of Computer Communications global positioning system (GPS) What is a _____________________________? 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. Uses of Computer Communications Collaboration • ____________________is working with other users connected to a server • Web conference Groupware • _______________is softwarethat allows peoplework together and share information p. 467 Fig. 9-7

  12. Uses of Computer Communications • ___________________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 p. 468 Fig. 9-8

  13. Networks p. 469 Fig. 9-9

  14. Networks What is a network? • Collection of computers and devices connected via communications devices and transmissionmedia p. 469 Fig. 9-9

  15. Networks Network classifications LAN • ____________is a network in limited geographical area such as home or office building • Wireless ____________ LAN (WLAN) LAN • _____________________________ connects _____s in city or town • _____________________________ Metropolitan area network (MAN) Wide area network (WAN) is a network that covers large geographic area using many types of media • ____________is world’s largest_________ Internet WAN

  16. Network Network Architectures Client/Server • _____________: One or more computers act as host computer and other computersaccess 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. peer-to-peer Internet peer-to-peer (P2P) p. 472 Fig. 9-13

  17. Network Network Topology: the layout of the computers in a network. Bus network • _____________: All computers and devices connect to central cable or bus p. 472 Fig. 9-13

  18. Network Network Topology Ring network • _____________: 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 p. 472 Fig. 9-13

  19. Network Network Topology Star network • _____________: All 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. Networks _________ allows customers or suppliers to access part of company’s __________ Makes information accessible to employees Typically includes connection to Internet Internal network that uses Internet technologies intranet What is an___________? Extranet intranet p. 475

  21. Network Communications Standards p. 476

  22. Network Communications Standards • ___________ technology allows computers to contend 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 Ethernet _______________ technology controls access to network by requiring devices to pass a special signal, calledtoken Token ring p. 476

  23. Network Communications Standards • _____________________________________________ • technology transmits data by breaking it up into • small pieces,or packets. • Commonly used for Internet transmissions TCP/IP (Transmission Control Protocol/Internet Protocol) _______________ is a family of standards for wireless LANs 802.11 (Wi-Fi) p. 476

  24. Network Communications Standards • ___________ Short-range radio waves transmitdata between Bluetooth devices • Contains a small chip to communicate with each other. Bluetooth _______ is aspecification allowsdata to be transferred wirelessly via short-rangeradio waves. WAB _______ specification allowsdata to be transferred wirelessly via infrared light waves. IrDA p. 476

  25. Network Communications Standards • ___________ uses radio signals to communicatewith a tag placed in an object • Radio Frequency Identification. RFID • _______ is astandard that specifies how wirelessdevices communicate over the airin a wide area. • Worldwide Interoperability for Microwave Access WiMAX • _______ allow wireless mobile devices to access Internet. • Wireless Application Protocol • Use client/server network. WAP p. 476

  26. Communications Software

  27. Communications Software What is communications software? • Programs that help usersestablish connection to Internet, other network, or another computer • Programs that help users manage transmission ofdata, instructions, and information • Programs that provide aninterface for users tocommunicate with one another p. 480

  28. Communications Over the Telephone Network p. 481 Fig. 9-23

  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. Communications Over the Telephone Network Various lines that use the telephone network for data communications dial-up line • _______________ 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 Dedicated line • _______________ Always-on connection between two communications devices • There are five types of lines. p. 481

  31. Communications Over the Telephone Network Dedicated lines • _______________ Integrated Services Digital Network. Require both ends of the connection have ________ modem. ISDN lines ISDN • __________Digital Subscriber Line For the small business or home user DSL • __________Fiber to the Premises Use fiber-optic cable to provide extremely high-speed Internet access FTTP p. 481

  32. Communications Over the Telephone Network Dedicated lines • _______________ Long-distance digital telephone lines that carry multiple signals over a single communications line. T1 line is most popular. T-Carrier lines • __________ Asynchronous Transfer Mode Very high speed. Large amounts of traffic use this. ATM p. 481

  33. Communications Devices p. 484

  34. Communications Devices Dial-up modem _________________ • Converts digital signals to analog signals and vice versa • Usually in the form of an adapter card p. 485

  35. Communications Devices ISDN and DSL modems What are____________________ ? 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 p. 485

  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 modem p. 484 - 486 Fig. 9-28

  37. Communications Devices wireless modem 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

  38. Communications Devices network card What is a______________? • 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. Communications Devices wireless access point What is a_____________________? • Central communications device that allows computers and devices to transfer data wirelessly among themselves or wirelessly to a wired network p. 487 Fig. 9-31

  40. Communications Devices What 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. Communications Devices What is a_______________? hub or switch • Device that provides central point for cables in network

  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 Transmission mediaare materials or substances capable of carrying one or more signals Bandwidthis amount of data that can travel over a communications channel

  45. Physical Transmission Media What is physical transmission media? • Wire, cable, and other tangible materials used to send communications signals p. 492 Fig. 9-36

  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 wiring p. 493 Fig. 9-37—9-38

  47. Physical Transmission Media fiber-optic 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? • Used when inconvenient, impractical, or impossible to install cables • Includes Bluetooth and IrDA p. 494 Fig. 9-40

  49. Wireless Transmission Media • ________________distributes radio signals over long and short distances Broadcast radio Cellular radio • ________________is form of ________________used for mobile communications broadcast radio

  50. Wireless Transmission Media microwave What is a __________station? • Earth-based reflective dish used for microwave communications • Must transmit in straight line with no obstructions

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