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Your Interactive Guide to the Digital World
Discovering Computers 2012
Objec&ves Overview
Discuss the purpose of the components required for successful communica:ons and iden:fy various sending
and receiving devices
Describe the uses of computer communica:ons
List advantages of using a network, and differen:ate among LANs, MANs, and
WANs
Differen:ate between client/server and peer-‐to-‐
peer networks, and describe how a P2P network works
Differen:ate among a star network, bus network, and
ring network
Describe the various network communica:ons
standards
Discovering Computers 2012: Chapter 9 2 See Page 459 for Detailed Objec:ves
Objec&ves Overview
Explain the purpose of communica:ons
soRware
Describe various types of lines for
communica:ons over the telephone network
Describe commonly used communica:ons
devices
Discuss different ways to set up a home
network
Describe various physical and wireless transmission media
Discovering Computers 2012: Chapter 9 3 See Page 459 for Detailed Objec:ves
Communica&ons
• Computer communica&ons describes a process in which two or more computers or devices transfer data, instruc:ons, and informa:on
Discovering Computers 2012: Chapter 9 4 Page 460
Sending device Communica&ons channel Receiving device
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Communica&ons
Discovering Computers 2012: Chapter 9 5 Pages 460 – 461 Figure 9-‐1
Uses of Computer Communica&ons
Blogs Chat rooms E-‐mail Fax
FTP Instant messaging Internet Newsgroups
RSS Video conferencing VoIP Web
Web 2.0 Web folders Wikis
Discovering Computers 2012: Chapter 9 6 Page 462
Uses of Computer Communica&ons
• Users can send and receive wireless messages using wireless messaging services
Discovering Computers 2012: Chapter 9 7 Pages 462 – 463 Figure 9-‐3
Uses of Computer Communica&ons
Text messaging (SMS) allows users to send and receive short text messages on a phone or other mobile device or computer
Picture messaging allows users to send pictures and sound files
Video messaging allows users to send short video clips
Wireless instant messaging allows wireless users to exchange real-‐:me messages with one or more other users
Discovering Computers 2012: Chapter 9 8 Pages 463 -‐ 464
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Uses of Computer Communica&ons
• Wireless Internet access points allow people to connect wirelessly to the Internet from home, work, school, and in many public loca:ons
Discovering Computers 2012: Chapter 9 9 Pages 464 – 465 Figure 9-‐4
Uses of Computer Communica&ons
• A cybercafé is a coffeehouse, restaurant, or other loca:on that provides personal computers with Internet access to its customers
Discovering Computers 2012: Chapter 9 10 Page 466 Figure 9-‐5
Uses of Computer Communica&ons
• A global posi&oning system (GPS) is a naviga:on system that consists of one or more earth-‐based receivers that accept and analyze signals sent by satellites in order to determine the GPS receiver’s geographic loca:on
• GPS receivers are:
Discovering Computers 2012: Chapter 9 11 Page 466
Built into many mobile
devices
Available as a handheld device
Available with new vehicles
Uses of Computer Communica&ons
Discovering Computers 2012: Chapter 9 12 Page 467 Figure 9-‐6
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Uses of Computer Communica&ons
Groupware
• Helps groups of people work together on projects and share informa:on over a network
• Component of workgroup compu:ng
• Major feature is group scheduling
Voice mail
• Allows someone to leave a voice message for one or more people
• Computer in voice mail system converts an analog voice message into digital form
• A voice mailbox is a storage loca:on on a hard disk in the voice mail system
Discovering Computers 2012: Chapter 9 13 Page 467
Uses of Computer Communica&ons
• Many programs provide a means to collaborate, or work online, with other users connected to a server
• Collabora:on soRware includes tools that enable users to share documents via online mee:ngs and communicate with other connected users
Discovering Computers 2012: Chapter 9 14 Page 468
Online mee:ngs
Web conferences
Document management
systems
Uses of Computer Communica&ons
Discovering Computers 2012: Chapter 9 15 Page 468 Figure 9-‐7
Uses of Computer Communica&ons
• Web services enable programmers to create applica:ons that communicate with other remote computers over the Internet or on an internal business network
• A mashup is a Web applica:on that combines services from two or more sources
Discovering Computers 2012: Chapter 9 16 Page 469 Figure 9-‐8
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Networks
• A network is a collec:on of computers and devices connected together via communica:ons devices and transmission media
• Advantages of a network include:
Discovering Computers 2012: Chapter 9 17 Pages 470 -‐ 471
Facilita:ng communica:ons
Sharing hardware
Sharing data and informa:on
Sharing soRware
Transferring funds
Networks
Discovering Computers 2012: Chapter 9 18 Page 470 Figure 9-‐9
Networks
• A local area network (LAN) is a network that connects computers and devices in a limited geographical area
• A wireless LAN (WLAN) is a LAN that uses no physical wires
Discovering Computers 2012: Chapter 9 19 Page 472 Figures 9-‐10 – 9-‐11
Networks
• A metropolitan area network (MAN) connects LANs in a metropolitan area
• A wide area network (WAN) is a network that covers a large geographical area
Discovering Computers 2012: Chapter 9 20 Page 473 Figure 9-‐12
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Networks
• The design of computers, devices, and media on a network is some:mes called the network architecture
Discovering Computers 2012: Chapter 9 21 Pages 473 – 474 Figures 9-‐13 – 9-‐14
Client/server network Peer-‐to-‐peer network
Networks
• P2P describes an Internet network on which users access each other’s hard disks and exchange files directly over the Internet
Discovering Computers 2012: Chapter 9 22 Page 475 Figure 9-‐15
Networks
• A network topology refers to the layout of the computers and devices in a communica:ons network
Discovering Computers 2012: Chapter 9 23 Pages 475 – 477 Figures 9-‐16 – 9-‐18
Star network Bus network Ring network
Networks
An intranet is an internal network that uses Internet
technologies
An extranet allows customers or
suppliers to access part of its intranet
Discovering Computers 2012: Chapter 9 24 Page 477
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Network Communica&ons Standards
Ethernet Token ring TCP/IP Wi-‐Fi
Bluetooth UWB IrDA RFID
WiMAX WAP
Discovering Computers 2012: Chapter 9 25 Page 477
Network Communica&ons Standards
Ethernet is a network standard that specifies no computer controls when data can be transmiied
The token ring standard specifies that computers and devices on the network share or pass a special signal (token)
TCP/IP is a network standard that defines how messages are routed from one end of a network to another
Discovering Computers 2012: Chapter 9 26 Page 478
Network Communica&ons Standards
Discovering Computers 2012: Chapter 9 27 Page 479 Figure 9-‐19
Network Communica&ons Standards
• Wi-‐Fi iden:fies any network based on the 802.11 standard that facilitates wireless communica:on
• Some:mes referred to as wireless Ethernet
Discovering Computers 2012: Chapter 9 28 Page 479 Figure 9-‐20
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Network Communica&ons Standards
• Bluetooth defines how two Bluetooth devices use short-‐range radio waves to transmit data
• UWB (ultra-‐wideband) specifies how two UWB devices use short-‐range radio waves to communicate at high speeds
• IrDA transmits data wirelessly via infrared (IR) light waves • RFID uses radio signals to communicate with a tag placed in
or aiached to an object, animal, or person
Discovering Computers 2012: Chapter 9 29 Pages 480 -‐ 481
Network Communica&ons Standards
Discovering Computers 2012: Chapter 9 30 Page 481 Figure 9-‐21
Network Communica&ons Standards
WiMAX (802.16)
• Developed by IEEE • Towers can cover a 30-‐mile radius
• Two types are fixed wireless and mobile wireless
• Provides wireless broadband Internet access
Wireless Applica&on Protocol (WAP)
• Specifies how some mobile devices can display the content of Internet services • Web • E-‐mail • Chat rooms
• Uses a client/server network
Discovering Computers 2012: Chapter 9 31 Page 482
Communica&ons So]ware
• Communica&ons so]ware consists of programs that:
Discovering Computers 2012: Chapter 9 32 Page 482
Help users establish a connec:on to
another computer or network
Manage the transmission of
data, instruc:ons, and informa:on
Provide an interface for users to communicate with one another
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Communica&ons Over the Telephone Network
• The public switched telephone network (PSTN) is the worldwide telephone system
Discovering Computers 2012: Chapter 9 33 Pages 482 – 483 Figure 9-‐23
Communica&ons Over the Telephone Network
Dial-‐up lines
Dedicated line ISDN line
DSL FTTP T-‐carrier line
ATM
Discovering Computers 2012: Chapter 9 34 Pages 483 -‐ 485
Communica&ons Over the Telephone Network
Discovering Computers 2012: Chapter 9 35 Page 483 Figure 9-‐24
Communica&ons Over the Telephone Network
• ADSL connec:ons transmit data downstream at a much faster rate than upstream
Discovering Computers 2012: Chapter 9 36 Page 484 Figure 9-‐25
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Communica&ons Devices
• A communica&ons device is any type of hardware capable of transmijng data, instruc:ons, and informa:on between a sending device and a receiving device
• A dial-‐up modem converts signals between analog and digital
Discovering Computers 2012: Chapter 9 37 Page 485
Communica&ons Devices
• A digital modem sends and receives data and informa:on to and from a digital line
Discovering Computers 2012: Chapter 9 38 Page 486
DSL modem
Cable modem
Communica&ons Devices
Discovering Computers 2012: Chapter 9 39 Page 486 Figures 9-‐26 – 9-‐27
Communica&ons Devices
• A wireless modem uses the cell phone network to connect to the Internet wirelessly from a notebook computer, a smart phone, or other mobile device
Discovering Computers 2012: Chapter 9 40 Page 487 Figure 9-‐28
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Communica&ons Devices
• A network card enables a computer or device to access a network
• Available in a variety of styles
• Wireless network cards oRen have an antenna
Discovering Computers 2012: Chapter 9 41 Page 487 Figure 9-‐29
Communica&ons Devices
• A wireless access point is a central communica:ons device that allows computers and devices to transfer data wirelessly among themselves or to a wired network
Discovering Computers 2012: Chapter 9 42 Page 487 Figure 9-‐30
Communica&ons Devices
• A router connects mul:ple computers or other routers together and transmits data to its correct des:na:on on a network
• Many are protected by a hardware firewall
Discovering Computers 2012: Chapter 9 43 Page 488 Figure 9-‐31
Communica&ons Devices
• A hub or switch connects several devices in a network together
Discovering Computers 2012: Chapter 9 44 Pages 488 – 489 Figure 9-‐32
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Home Networks
Discovering Computers 2012: Chapter 9 45 Page 489
• Home networks provide computers with the following capabili:es:
Connect to the Internet at the same :me
Share a single high-‐speed Internet
connec:on
Access files and programs on other
computers Share peripherals
Play mul:player games
Connect game consoles to the
Internet Subscribe to and
use VoIP
Home Networks
• Types of wired home networks:
Discovering Computers 2012: Chapter 9 46 Page 489
Ethernet Powerline cable
Phoneline
Home Networks
Discovering Computers 2012: Chapter 9 47 Page 490 Figure 9-‐33
Communica&ons Channel
• The amount of data that can travel over a communica:ons channel some:mes is called the bandwidth
• Latency is the :me it takes a signal to travel from one loca:on to another on a network
• Transmission media carries one or more signals
• Broadband media transmit mul:ple signals simultaneously
Discovering Computers 2012: Chapter 9 48 Page 491 Figure 9-‐34
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Physical Transmission Media
Discovering Computers 2012: Chapter 9 49 Page 492 Figure 9-‐35
Physical Transmission Media
Discovering Computers 2012: Chapter 9 50 Page 493 Figures 9-‐36 – 9-‐38
Twisted-‐pair cable
Coaxial cable
Fiber-‐op&c cable
Wireless Transmission Media
Discovering Computers 2012: Chapter 9 51 Page 494 Figure 9-‐39
Wireless Transmission Media
• Cellular radio is a form of broadcast radio that is used widely for mobile communica:ons
Discovering Computers 2012: Chapter 9 52 Pages 494 -‐ 495 Figure 9-‐40
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Wireless Transmission Media
• Microwaves are radio waves that provide a high-‐speed signal transmission
Discovering Computers 2012: Chapter 9 53 Page 496 Figure 9-‐41
Wireless Transmission Media
• A communica&ons satellite is a space sta:on that receives microwave signals from an earth-‐based sta:on, amplifies it, and broadcasts the signal over a wide area
Discovering Computers 2012: Chapter 9 54 Page 496 Figure 9-‐42
Video: Got Your Video Right Here
Discovering Computers 2012: Chapter 9 55
CLICK TO START
Summary
Overview of communica:ons terminology and applica:ons
How to join computers into a
network
Various communica:ons devices, media, and procedures
Discovering Computers 2012: Chapter 9 56 Page 497
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