Discovering Computers 2012Chapter 9Networks and Communications

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Your Interactive Guide to the Digital World

Discovering

Computers 2012 Chapter 9

Networks and Communications

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Objectives Overview

Discuss the purpose of the components required for successful communications and identify various sending

and receiving devices Discuss the purpose of the

components required for successful communications and identify various sending

and receiving devices

Describe the uses of computer communications

List advantages of using a network, and differentiate

among LANs, MANs, and WANs

List advantages of using a network, and differentiate

among LANs, MANs, and WANs

Differentiate between client/server and peer-to-

peer networks, and describe how a P2P

network works Differentiate between client/server and peer-to-

peer networks, and describe how a P2P

network works

Differentiate among a star network, bus network, and

ring network

Differentiate among a star network, bus network, and

ring network

Describe the various network communications

standards

Describe the various network communications

standards

Discovering Computers 2012: Chapter 9 2

See Page 459

for Detailed Objectives

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Objectives Overview

Explain the purpose of communications

software

Explain the purpose of communications

software

Describe various types of lines for

communications over the telephone network

Describe various types of lines for

communications over the telephone network

Describe commonly used communications

devices

Describe commonly used communications

devices

Discuss different ways to set up a home

network

Discuss different ways to set up a home

network

Describe various physical and wireless

transmission media Describe various physical and wireless

transmission media

See Page 459

for Detailed Objectives

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Communications

• Computer communications describes a process in which two or more computers or devices transfer data, instructions, and information

Page 460

Sending device

Sending device Communications channel

Communications

channel Receiving device Receiving device

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Communications

Pages 460 – 461 Figure 9-1

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Uses of Computer Communications

Blogs

Blogs Chat rooms Chat rooms E-mail E-mail Fax Fax

FTP FTP Instant messaging

Instant

messaging Internet Internet Newsgroups Newsgroups

RSS RSS Video conferencing

Video

conferencing VoIP VoIP Web Web

Web 2.0

Web 2.0 Web folders Web folders Wikis Wikis

Page 462

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Uses of Computer Communications

• Users can send and receive wireless messages using wireless messaging services

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Uses of Computer Communications

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-time messages with one or more other users

Pages 463 - 464

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Uses of Computer Communications

• Wireless Internet access points allow people to connect wirelessly to the Internet from home, work, school, and in many public locations

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Uses of Computer Communications

• A cybercafé is a coffeehouse, restaurant, or other location that provides personal computers with Internet access to its customers

Page 466 Figure 9-5

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Uses of Computer Communications

• A global positioning system (GPS) is 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 GPS receiver’s geographic location

• GPS receivers are:

Page 466

Built into many mobile

devices Built into many mobile

devices

Available as a handheld

device

Available as a handheld

device

Available with new vehicles Available with

new vehicles

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Discovering Computers 2012: Chapter 9 12 Page 467

Figure 9-6

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Uses of Computer Communications

Groupware Groupware

• Helps groups of people work together on projects and

share information over a network

• Component of workgroup computing

• Major feature is group scheduling

Voice mail 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 location on a hard disk in the voice mail system

Page 467

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Uses of Computer Communications

• Many programs provide a means to collaborate, or work online, with other users connected to a server

• Collaboration software includes tools that enable users to share documents via online meetings and communicate with other connected users

Page 468

Online meetings

Online

meetings Web

conferences Web

conferences

Document management

systems Document management

systems

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Figure 9-7

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Uses of Computer Communications

• Web services enable programmers to create applications that

communicate with other remote computers over the Internet or on an

internal business network

• A mashup is a Web

application that combines services from two or more sources

Page 469 Figure 9-8

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Networks

• A network is a collection of computers and

devices connected together via communications devices and transmission media

• Advantages of a network include:

Pages 470 - 471

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Figure 9-9

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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

Page 472

Figures 9-10 – 9-11

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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

Page 473 Figure 9-12

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Networks

• The design of computers, devices, and media on a

network is sometimes called the network architecture

Pages 473 – 474 Figures 9-13 – 9-14

Client/server network Peer-to-peer network

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Networks

• P2P describes an Internet network on which users access each other’s hard disks and exchange files directly over the Internet

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Networks

• A network topology refers to the layout of the computers and devices in a communications network

Pages 475 – 477 Figures 9-16 – 9-18

Star network Bus network Ring network

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Networks

Page 477

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Network Communications Standards

Page 477

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Network Communications Standards

Page 478

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Figure 9-19

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Network Communications Standards

• Wi-Fi identifies any network based on the 802.11 standard that facilitates wireless communication

• Sometimes referred to as wireless Ethernet

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Network Communications 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 attached to an object, animal, or person

Pages 480 - 481

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Figure 9-21

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Network Communications Standards

Page 482

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Communications Software

• Communications software consists of programs that:

Page 482

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Communications Over the Telephone Network

• The public switched telephone network (PSTN) is the worldwide telephone system

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Communications Over the Telephone Network

Pages 483 - 485

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Communications Over the Telephone Network

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Communications Over the Telephone Network

• ADSL connections transmit data downstream at a much faster rate than upstream

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Communications Devices

• A communications device is any type of hardware capable of transmitting data, instructions, and

information between a sending device and a receiving device

• A dial-up modem converts signals between analog and digital

Page 485

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Communications Devices

• A digital modem sends and receives data and information to and from a digital line

Page 486

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Communications Devices

Page 486

Figures 9-26 – 9-27

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Communications 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

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Communications Devices

• A network card enables a computer or device to access a network

• Available in a variety of styles

• Wireless network cards often have an antenna

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Communications Devices

• A wireless access point is a central communications

device that allows computers and devices to transfer data wirelessly among themselves or to a wired network

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Communications Devices

• A router connects

multiple computers or other routers together and transmits data to its correct destination on a network

• Many are protected by a hardware firewall

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Communications Devices

• A hub or switch connects several devices in a network together

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Home Networks

Page 489

• Home networks provide computers with the following capabilities:

Connect to the Internet at the

same time Connect to the Internet at the

same time

Share a single high- speed Internet

connection Share a single high-

speed Internet connection

Access files and programs on other

computers Access files and programs on other

computers Share peripherals Share peripherals

Play multiplayer games

Connect game consoles to the

Internet Connect game consoles to the

Internet

Subscribe to and use VoIP Subscribe to and

use VoIP

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Home Networks

• Types of wired home networks:

Page 489

Ethernet

Ethernet Powerline cable Powerline cable

Phoneline

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Figure 9-33

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Communications Channel

• The amount of data that can travel over a communications channel sometimes is called the bandwidth

• Latency is the time it takes a signal to travel from one

location to another on a network

• Transmission media carries one or more signals

• Broadband media transmit multiple signals simultaneously

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Figure 9-35

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Figures 9-36 – 9-38

Twisted-pair cable

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Figures 9-36 – 9-38

Coaxial cable

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Figures 9-36 – 9-38

Fiber-optic cable

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Figure 9-39

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Wireless Transmission Media

• Cellular radio is a form of broadcast radio that is used widely for mobile communications

Pages 494 - 495 Figure 9-40

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Wireless Transmission Media

• Microwaves are radio waves that provide a high- speed signal transmission

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Wireless Transmission Media

• A communications satellite is a space station that receives

microwave signals from an earth-based station, amplifies it, and

broadcasts the signal over a wide area

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Video: Got Your Video Right Here

CLICK TO START

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Summary

Overview of communications terminology and

applications Overview of communications terminology and

applications

How to join

computers into a network

How to join

computers into a network

Various

communications devices, media, and procedures

Various

communications devices, media, and procedures

Page 497

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Your Interactive Guide to the Digital World

Discovering

Computers 2012 Chapter 9

Networks and Communications

Chapter 9 Complete

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9A-61

Project due Nov. 16

• Play the game of FreeCell.

• small number on next larger number and alternating color

• e.g. Heart Queen on Club King and Spade Jack on Heart Queen

• goal: to throw all cards to destination pile

• current smallest number of the suit: can be thrown to destination pile

• any card can be moved to empty line (stack)

• any card can be moved to temporary work space (TMP)

• Print every step.

• Your last two digits + 1000 are the game number you have to solve.

• Game #617:

• HQ  CK, S2  TMP, SJ  HQ, C10  DJ, HK  TMP, HK  Line8,

• SK  TMP, S10  TMP, SQ  HK, HJ  SQ, S10  HJ, H4  TMP,

• D5  C6, H9  S10, C3  TMP, D9  C10, C3 throw, S3  TMP,

• H4  Line4, S3  H4, D4  TMP, D3  TMP, D2  S3, C10  Line7,

• H5  TMP, DJ  CQ, S4  D5, C4 throw, D3  S4, CQ  DK,

• C10  DJ, S7  TMP, SK  Line7, HQ  SK, D4 throw, S3 throw,

• S4 throw, H5  C6, CK  TMP, C9  TMP, S9  TMP, CK  Line4,

• DQ  CK, CJ  DQ, C7 throw, H6 throw, S8  H9, H7  S8,

• S6  H7, D6 throw, S8 throw, S9 throw, CQ  Line2, DK  TMP,

• H10  TMP, D10  TMP