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Chapter 9Communications
and Networks
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Chapter 9 Objectives
Discuss the components required forsuccessful communications
Discuss the components required forsuccessful communications
Identify various sending
and receiving devices
Identify various sending
and receiving devices
Describe uses of computer communications
Describe uses of computer communications
List advantages of using a network
List advantages of using a network
Differentiate among client/server,peer-to-peer, and P2P networks
Differentiate among client/server,peer-to-peer, and P2P networks
Describe the various network
communications standards
Describe the various network
communications standards
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
Identify various physical and wireless
transmission media
Identify various physical and wireless
transmission media
Next
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Communications
What are computer communications?
Nextp. 460 Fig. 9-1
Process in which two or more computers or devices transfer data,
instructions, and information
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Uses of Computer Communications
What are some uses of communications technology?
Nextp. 462
WebWeb
WebWebInternetInternet
InternetInternet EE--MailMail
EE--MailMailInstantInstant
MessagingMessaging
InstantInstantMessagingMessaging
InternetInternet
TelephonyTelephony
InternetInternet
TelephonyTelephonyNewsgroupsNewsgroups
NewsgroupsNewsgroupsChat RoomsChat Rooms
Chat RoomsChat Rooms
WebWeb
FoldersFolders
WebWeb
FoldersFolders
Fax MachineFax Machine
orComputerorComputerFax/ModemFax/Modem
Fax MachineFax Machine
orComputerorComputerFax/ModemFax/Modem
VideoVideo
ConferencingConferencing
VideoVideo
ConferencingConferencingFTPFTP
FTPFTP
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Uses of Computer Communications
What are wireless Internetaccess points and
cybercafs?
Nextp. 464 Fig. 9-5
Wireless Internet access
point allows wirelessconnection to Internetin public location
3G network
Cybercaf is coffee
house that providescomputers with Internetaccess
Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickHot Spots belowChapter 9
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Uses of Computer Communications
What is a global positioning system (GPS)?
Nextp. 466 Fig. 9-6
Step 1.GPS satellites orbit
Earth. Every
thousandth of a
second, each satellitesends a signal that
indicates its current
position to the GPS
receiver.
Step 2.A GPS receiver
(such as in a car,,
a watch, a smartphone, a
handheld device,
or a collar)
determines its
location on Earth
by analyzing at
least 3 separate
satellite signalsfrom the 24
satellites in orbit.
Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickGPS belowChapter 9
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Uses of Computer Communications
What are collaboration andgroupware?
Nextp. 467 - 468 Fig. 9-7
A document management
system provides for storage
and management of a
companys documents
Groupware is software
that allows people
to share
information
Collaboration is working
with other users connected
to a server
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Uses of Computer Communications
What are voice mail and web services?
Nextp. 468 Fig. 9-8
Voice mail is voice message
converted to digital form
Web services describe
standardized software thatenables programmers to
create applications that
communicate with other
remote computers over theInternet or on an internal
business network
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Networks
What is a network?
Nextp. 469 Fig. 9-9
Collection ofcomputers anddevices connectedvia communications
devices andtransmissionmedia
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Networks
What is a local areanetwork (LAN)?
Nextp. 471 472 Fig. 9-10
Network in limited geographical area such ashome or office building
Wireless LAN (WLAN)
Metropolitan area network (MAN) connects LANs incity or town
Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickWireless LocalArea NetworksbelowChapter 9
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Networks
What is a wide areanetwork (WAN)?
Nextp. 472 Fig. 9-12
Network that covers
large geographic
area using manytypes of media
Internet is worlds
largestWAN
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Networks
What is a client/servernetwork?
Nextp. 472 Fig. 9-13
One or more computersact as server and othercomputers, or clients,access server
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Networks
What is a peer-to-peernetwork?
Nextp. 473 Fig. 9-14
Simple network
that connects
fewer than 10computers
Each computer,
or peer, has equal
capabilities
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Networks
What is Internet peer-to-peer(P2P)?
Nextp. 473 - 474 Fig. 9-15
Enables users to
connect to each others
hard disks andexchange files directly
Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickP2P belowChapter 9
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Networks
What is a bus network?
Nextp. 474 Fig. 9-16
All computers and devices connect to central
cable,
or bus Example ofnetwork topology (layout of devices in
network)
Popular topologies are bus, ring, and star
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Networks
What is a ring network?
Nextp. 474 Fig. 9-17
Cable forms closed
ring, or loop, with all
computers and devices
arranged along ring Data travels from
device to device
around entire ring, in
one direction
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Networks
What is a star network?
Nextp. 475 Fig. 9-18
All devices connect to
a central device, called
hub
All data transferredfrom one computer to
another passes
through hub
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Networks
What is an intranet?
Nextp. 475
Extranet allows customers or suppliers to access
part of companys intranet
Typically includes connection to Internet
Makes information accessible to employees
Internal network that uses Internet technologies
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Network Communications Standards
What are Ethernet and token ring?
Nextp. 476
Ethernet technology allows computers to contend
for access to network
If two computers send data at same time,a collision occurs and computers must send again
Token ring technology controls access to networkby requiring devices to pass a special signal,
called tokenClick to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickEthernet belowChapter 9
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Network Communications Standards
What are TCP/IP and 802.11 (Wi-Fi)?
Nextp. 477 - 478 Fig. 9-20
TCP/IP (Transmission Control Protocol/Internet
Protocol) technology transmits data by breaking it up
into small pieces, or packets
Commonly used for Internet transmissions
802.11 (Wi-Fi) is family of standards for wireless LANs
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Network Communications Standards
What is Bluetooth?
Nextp. 478
Short-range radio waves transmit
data between Bluetooth devices
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Network Communications Standards
What are IrDA, RFID, WiMAX, and WirelessApplications Protocol (WAP)?
Nextp. 478 - 480
Click to view WebLink, clickChapter 9,Click Web Link from leftnavigation, then clickWiMAX belowChapter 9
IrDAIrDAspecification allows
data to be transferredwirelessly via infrared
light waves
IrDAIrDAspecification allows
data to be transferredwirelessly via infrared
light waves
Wireless ApplicationsWireless Applications
Protocol (WAP)Protocol (WAP)allow wireless mobile devices
to access Internet
Wireless ApplicationsWireless Applications
Protocol (WAP)Protocol (WAP)allow wireless mobile devices
to access Internet
Radio FrequencyRadio Frequency
Identification (RFID)Identification (RFID)uses radio signals to communicate
with a tag placed in an object
Worldwide InteroperabilityWorldwide Interoperability
for Microwave Access (WiMAXfor Microwave Access (WiMAX
or 802.16)or 802.16)
standard that specifies how wirelessdevices communicate over the air
in a wide area
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Video: Keep Tabs on Your Pets
Discover how to improve the odds of recovering a lost orstolen pet
low quality
(click to start)
high quality(click to start)
Next
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Communications Software
What is communications software?
Nextp. 480
Programs that help users
establish connection to
Internet, other network,
or another computer Programs that help usersmanage transmission of
data, instructions,
and information
Programs that provide an
interface for users to
communicate with oneanother
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Communications Over the Telephone Network
What is the public switchedtelephone network (PSTN)?
Nextp. 481 Fig. 9-23
Worldwide telephone
system that handles
voice-orientedtelephone calls
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Communications Over the Telephone Network
What is a dial-up line?
Nextp. 481
Temporary connection using telephone line for
communications
Costs no more than making regular call
Computers at any two locations can establish aconnection using modems and telephone network
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Communications Devices
What are examples ofcommunications devices?
Nextp. 484
Common types are dial-up modems, ISDN and
DSL modems, cable modems, network cards,
wireless access points, routers, and hubs
ISDN and DSL modems send
and receive data from ISDN
and DSL lines
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Communications Devices
What is a dial-up modem?
Nextp. 485 Figs. 9-27
Converts digital signals to analog signals and vice versa
Notebook computers often use PCCard modem
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Communications Devices
What are ISDN and DSL modems?
Nextp. 485
Communications devices that send and
receive digital ISDN and DSL signals
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
Usually external devices in which one
end connects to a telephone line and the other
end connects to a port on the system unit
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Communications Devices
What is a cable modem?
Nextp. 485 - 486 Fig. 9-28
Sends and receives
data over cable
television network
Much faster than
dial-up modem orISDN
Sometimes called a
broadband modem
Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickCable ModemsbelowChapter 9
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Communications Devices
What is a wireless modem?
Nextp. 486 Fig. 9-29
Allows access to the
Web wirelessly from
a notebook
computer, a PDA, asmart phone, or
other mobile device
Typically use the
same waves used bycellular telephones
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Communications Devices
What is a network card?
Nextp. 486 Fig. 9-30
Adapter card, PC
Card, or flash card
that enables
computer or deviceto access network
Sometimes called
network interface
card (NIC)
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Communications Devices
What is a wireless access point?
Nextp. 487 Fig. 9-31
Central
communications
device that allows
computers and
devices to transfer
data wirelessly among
themselves or
wirelessly to a wired
network
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Communications Devices
What is a router?
Nextp. 488 Fig. 9-32
Connects computers and
transmits data to correct
destination on network
Routers forward data onInternet using fastest available
path
Click to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickHardware Firewalls belowChapter 9
Some routers have a built-in
hardware firewall
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Communications Devices
What is a hub?
Nextp. 488 - 489 Fig. 9-33
Device that provides central
point for cables in network
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Home Networks
What is a home network?
Nextp. 489 - 490 Fig. 9-34
Multiple computers
connected in home
Several types of home
networks
Ethernet connect
computers via cable
Powerline cable use electrical lines in house
Phoneline
usetelephone lines
HomeRF (radio frequency)wirelessClick to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickHome NetworksbelowChapter 9
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Communications Channel
What is a communications channel?
Nextp. 491
Transmission media on which data travels in
communications system
Bandwidth is amount of
data that can travel
over a communicationschannel
Transmission mediaare materials capable of
carrying one or more
signals
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Communications Channel
How is a request sent over theInternet using a communications
channel?
Nextp. 491 Fig. 9-35
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Physical Transmission Media
What is physical transmission media?
Nextp. 492 Fig. 9-36
Wire, cable,and other tangiblematerials usedto send
communicationssignals
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Physical Transmission Media
What are twisted-pair cable and coaxial cable?
Nextp. 493 Fig. 9-379-38
Twisted-pair cable is used for telephone systems and network cabling
Coaxial cable is often used for cable television wiring
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Wireless Transmission Media
What is wireless transmission media?
Nextp. 494 Fig. 9-40
Used when inconvenient, impractical, or impossible to
install cables
Includes Bluetooth and IrDA
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Wireless Transmission Media
What are broadcast radio and cellular radio?
Nextp. 494 Fig. 9-41
Broadcast radio
distributes radio
signals over long
and short distances Cellular radio
is form of
broadcast radio
used for mobile
communicationsClick to view WebLink, clickChapter 9, ClickWeb Link from leftnavigation, then clickCellularCommunications belowChapter 9
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Wireless Transmission Media
What is a microwave station?
Nextp. 495 Fig. 9-42
Earth-based
reflective
dish used for
microwave
communications
Must transmit in
straight line with
no obstructions
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Wireless Transmission Media
What is a communications satellite?
Nextp. 496 Fig. 9-43
Space station
that receives
microwave signals
from earth-based
station, amplifiessignals, and
broadcasts signals
back to any
number of earth-
based stations
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Summary of Communications and Networks
Chapter 9 Complete
Communications terminologyand applications
Communications terminologyand applications
How to join computers into a networkHow to join computers into a network
Various communicationsdevices, media, and procedures
Various communicationsdevices, media, and procedures