Download Discovering Computers 2009

Discovering
Computers 2009
Chapter 9
Communications
and Networks
Chapter 9 Objectives
Discuss the components required for
successful communications
Identify various sending
and receiving devices
Explain the purpose of
communications software
Describe various types of lines for
communications over the telephone network
Describe 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
Describe the various network
communications standards
Identify various physical and wireless
transmission media
Communications
Communications
communications
What are computer___________________?

Process in which two or more computers or devices transfer data,
instructions, and information
Communications
What is needed for successful communications?
Sending device
__________________—
Communications
initiates instruction to
device — connects
transmit data,
the sending device to
instructions, or
the communications
information
channel
Communications
device — connects
the communications
channel to the
receiving device
p. 460 - 461
Communications channel
__________________
media
on which data,
instructions, or
information travel
Receiving device
_________________
accepts transmission of
data, instructions, or
information
Uses of Computer Communications
Uses of Computer Communications
What are some uses of communications technology?
p. 462
Internet
Web
E-Mail
Instant
Messaging
Chat Rooms
Newsgroups
Blogs
Wikis
RSS
VoIP
FTP
Web Folders
Video
Conferencing
Fax Machine
or Computer
Fax/Modem
Uses of Computer Communications
What are wireless messaging services?
Text messaging
allows users to send
and receive short
text messages on a
phone or other
mobile device
p. 463 - 464
Wireless instant
messaging allows
wireless mobile
devices to exchange
messages
Picture/video
messaging allows
users to send
graphics, pictures,
video clips, sound
files, and short text
messages
Uses of Computer Communications
wireless Internet access points
What are _______________________________
 allows wireless
connection to Internet
in public location
 3G and 4G
networks
Cybercafé
 _______________is
a
coffee house that
provides computers
with Internet access
p. 464-465 Fig. 9-4
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
Uses of Computer Communications
Collaboration
 ____________________is
working with other users connected
to a server
 Web conference
Groupware
 _______________is
software that allows people work together
and share information
p. 467 Fig. 9-7
Uses of Computer Communications
Voice mail
 ___________________is
voice message converted
to digital form
Web services
 _____________________describe
standardized
software that enables programmers to create
applications that communicate with other remote
computers over the Internet or on an internal
business network
p. 468 Fig. 9-8
Networks
p. 469 Fig. 9-9
Networks
What is a network?
 Collection of
computers and
devices connected
via communications
devices and
transmission
media
p. 469 Fig. 9-9
Networks
Network classifications
LAN
 ____________is
a network in limited geographical area
such as home or office building

LAN (WLAN)
Wireless ____________
LA
 _____________________________
Metropolitan area network (MAN) connects _____s
N
in city or town
Wide area network (WAN)
is a network that
 _____________________________
covers large geographic area using many types of media
Internet
WAN
 ____________is
world’s largest_________
Network
Network Architectures
Client/Server
 _____________:
One or more computers act as host
computer and other computers access the host
computer
peer-to-peer
 _______________:
Simple network that connects fewer
than 10 computers. Each computer has equal
capabilities
Internet peer-to-peer (P2P)
 _________________________:
Enables users to
connect to each other’s hard disks and exchange files
directly. Sometimes called a file sharing network.
p. 472 Fig. 9-13
Network
Network Topology: the layout of the computers in a
network.
Bus network
1. _____________:
All computers and devices connect to
central cable or bus
p. 472 Fig. 9-13
Network
Network Topology
Ring network Cable
2. _____________:
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
Network
Network Topology
Star network
3. _____________:
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
Networks
intranet
What is an___________?
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
Network Communications Standards
p. 476
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 token
p. 476
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
802.11 (Wi-Fi) is a family of standards for
_______________
wireless LANs
p. 476
Network Communications Standards
___________
Bluetooth Short-range radio waves transmit
data between Bluetooth devices
• Contains a small chip to communicate with each other.
WAB is a specification allows data to be
_______
transferred wirelessly via short-range radio waves.
IrDA specification allows data to be transferred
_______
wirelessly via infrared light waves.
p. 476
Network Communications Standards
___________
uses radio signals to communicate
RFID
with a tag placed in an object
• Radio Frequency Identification.
WiMAX is a standard that specifies how wireless
_______
devices communicate over the air in a wide area.
• Worldwide Interoperability for Microwave Access
WAP allow wireless mobile devices
_______
to access Internet.
• Wireless Application Protocol
• Use client/server network.
p. 476
Communications Software
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 another

p. 480
Communications Over the Telephone Network
p. 481 Fig. 9-23
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
Communications Over the Telephone Network
Various lines that use the telephone network for data
communications
dial-up line
1. _______________
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
2. _______________
Always-on connection between
two communications devices
 There are five types of lines.
p. 481
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 highspeed Internet access
p. 481
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
Communications Devices
p. 484
Communications Devices
Dial-up modem
_________________

p. 485
Converts digital signals to analog signals and vice versa
 Usually in the form of an adapter card
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
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
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
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
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
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
Communications Devices
What is a_______________?
hub or switch
 Device that provides central
point for cables in network
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
Communications Channel
Communications Channel
What 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
signals
Bandwidth is amount of
data that can travel
over a communications
channel
Physical Transmission Media
What is physical transmission media?

Wire, cable, and other tangible materials used
to send communications signals
p. 492 Fig. 9-36
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
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
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
Wireless Transmission Media
Broadcast radio
 ________________
distributes radio
signals over long
and short distances
Cellular radio
 ________________
is form of
broadcast radio
________________
used for mobile
communications
Wireless Transmission Media
microwave
What is a __________station?
 Earth-based
reflective
dish used for
microwave
communications
 Must transmit in
straight line with
no obstructions
Wireless Transmission Media
communications satellite
What is a_______________________?
 Space station
that receives microwave
signals from earth-based
station, amplifies signals,
and broadcasts signals
back to any number of
earth-based stations
Summary of Communications and Networks
Communications terminology
and applications
Various communications
devices, media, and procedures
How to join computers into a network
Chapter 9 Complete