Instructor's Manual Materials to Accompany

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Copyright ©
2008
Prentice
-
Hall. All rights reserved.


Instructor’s Manual Materials to Accompany

COMPUTERS ARE YOUR F
UTURE

CHAPTER 3

WIRED & WIRELESS COM
MUNICATION

CHAPTER
ANSWERS TO END
-
OF
-
CHAPTER QUESTIONS

Matching


1.


digitization

j

2.


b
roadband

o

3.


SONET

n

4.


PSTN

a

5.


w
ireless

b

6.


l
ast
-
mile technologies

c

7.


c
onvergence

d

8.


l
eased line

m

Chapter 3: Wired
&
Wireless Communication

Copyright ©
2008
Prentice
-
Hall. All rights reserved.


2


9.


c
ell

e

10.


m
icrowaves

g

11.


T1 line

f

12.


v
ideoconferencing

i

13.


t
wisted

pair

h

14.


PCS

k

15.


analog

signal

l

Multiple
Choice


1.

What type of line us
es fiber
-
optic cables?

a.

T1

b.

T2

c.

T3

d.

10baseT

c

Chapter 3: Wired
&
Wireless Communication

Copyright ©
2008
Prentice
-
Hall. All rights reserved.


3


2.

Which of the following media carries more data for longer distances?

a.

digital coaxial cable

b.

c
oaxial cable

c.

t
wisted
-
pair wire

d.

f
iber
-
optic cable

d

3.

Which of the following is not a transmission medium used to provide regional and long
-
distance
service between local telephone exchanges?

a.

m
icrowaves

b.

f
iber
-
optic cables

c.

c
ommon carrier

d.

c
opper wire

a

4.

Which term des
cribes a cell phone's capability to indicate a user's whereabouts?

a.

location awareness

b.

self
-
awareness

c.

global awareness

d.

location global positioning

a

5.

What does DBS stand for?

a.

Digital Band Service

b.

Digital Band Service

c.

Dig
ital Broadband Service

d.

Direct Broadcast Satellite

d

Chapter 3: Wired
&
Wireless Communication

Copyright ©
2008
Prentice
-
Hall. All rights reserved.


4

6.

When someone makes a cellular phone call, all of the cell sites are connected to which of the
following?

a.

p
ublic switched telephone network (PSTN)

b.

m
obile optical netwo
rk (MONET)

c.

Mobile Digital Subscriber Line (MDSL)

d.

m
obile telephone switching office (MTSO)

d

7.

What is multiplexing?

a.

a

multiscreen movie theater

b.

m
any interconnected networks

c.

t
he ability to transmit more than one call on a

single line

d.

t
he ability to send data and faxes with a single device

c

8.

Which of the following services requires broadband digital transmission?

a.

d
igital television

b.

f
axing

c.

s
ending e
-
mail

d.

n
one of the above

a

9.

Which of the following terms is a technology that could be used for a wireless keyboard?

a.

InDA

b.

Serial

c.

IrDA

d.

InFRA

c

Chapter 3: Wired
&
Wireless Communication

Copyright ©
2008
Prentice
-
Hall. All rights reserved.


5


10.

What videoconferencing technology enables participants to create a shared workspace?

a.

T2 lines

b.

instant messaging

c.

whi
teboard

d.

fax modem

c


Fill

in the Blank


1.

A(n)
___________

___________ ___________
is a small, waist
-
high curbside installation that
connects as many as 96 telephone subscribers.

subscriber loop carrier

2.

The area served by an SLC is called the
___________
___________.

local loop

3.

A(n)
___________

is a device that enables computers to access the Internet by means of a cable TV
connection.

modem or
c
able modem

4.

___________

___________

allows you to send full
-
color pictures, backgrounds, and even picture
caller IDs on your cell phone.

Picture messaging

5.

___________

is the transformation of data such as voice, text, graphics, audio, and video into digital

form.

D
igitization

6.

If your computer is equipped with a(n)
___________

___________
you can send and receive faxes
from your computer.

fax modem

7.

___________

___________

uses the Internet for real
-
time voice communicatio
n.

Internet telephony

Chapter 3: Wired
&
Wireless Communication

Copyright ©
2008
Prentice
-
Hall. All rights reserved.


6

8.

Communications
___________

are placed in geosynchronous orbit, which matches the speed of the
Earth's rotation.

satellites

9.

When using
___________
, no wires ar
e required, but the transmitter and receiver must be in line of
sight or the signal is lost.

infrared

10.

___________

can be described as "low" or "high” as it refers to transmission speeds.

Bandwidth

11.

___________

refers collectively to a group of related digit
al cellular technologies.

PCS

12.

___________

__________

uses two insulated wires twisted around each other to shield against
interference.

Twisted

pair

13.

A(n
) _
__________

___________
converts data into discontinuous pulses
in which the presence or
absence of electronic pulses represents 1s and 0s .

digital signal

14.

Within a range of approximately 30 feet,
___________

allows for the transfer of data between itself
and other enabled devices.

Bluetooth

15.

The inability of homes or businesses to access the PSTN's high
-
speed fiber
-
optic cables is often
referred to as the
___________ __________
___________
.

last mile problem

Short Answer


1.

What is bandwidth? Why is it an important consideration when connecting to the Internet?

Bandwidth
refers to the amount of data that can be transmitted through a given communications channel.
Exploring the Web is a more pleasant proposition

if you use a transmission medium with high bandwidth or a
data transfer rate of 128 Kbps or faster.

2.

A computer must have a fax modem and a scanner to fully function as a fax device. Explain why the scanner
is needed.

Chapter 3: Wired
&
Wireless Communication

Copyright ©
2008
Prentice
-
Hall. All rights reserved.


7

A
fax modem

is a computerized version of a stand
-
alone fax machine. This device and software allow your
computer to do everything a fax machine can: send and receive documents, print documents, and store
documents. The big difference between using a regula
r fax machine and using your computer as a fax
machine is that the fax modem does everything in a digitized way. So, you may need a scanner to put a
document into a digital format if you want to fax something that's printed or sketched on paper.

3.

In terms of the last
-
mile problem, explain the limitations of the PSTN for sending and receiving computer
data.

The inability of homes or businesses to access the PSTN's high
-
speed fiber
-
optic cables, along with the
bottleneck o
f data on the last mile of twisted
-
pair phone lines connecting homes and businesses, is often
referred to as the
last
-
mile problem
.

In most areas of the United States, only the local loop is still using
analog technology, because nearly all existing buildi
ngs were originally constructed with built
-
in twisted
-
pair
wiring. These analog lines are vulnerable to noise and can't surpass a theoretical limit of 56 Kbps. For the
local loop to change over to digital lines, all of this wiring would have to be redone

a
n expense that is
simply too great. The cost to replace all the twisted

pair
wiring
that currently delivers phone service to homes
and offices worldwide would be upwards of $325 billion, and that is not likely to happen anytime soon. So
,

in
the meantime, c
omputer users desiring high
-
speed data communications can consider a number of "
last
-
mile"
technologies as well as wireless options.

4.

Define convergence. Provide at least one example of technological convergence.

Conver
gence
refers to the merging of disparate objects or ideas (and even people) into new combinations.
Within the IT industry, convergence means two things: (1) the combination of various industries (computers,
consumer electronics, and telecommunications) and

(2) the coming together of products such as PCs and
telephones. Web
-
enabled PDAs, some cell phones, and tablet PCs would be considered examples of
technological convergence.

5.

Briefly explain how Bluetooth works.

Blueto
oth
-
enabled devices identify each other using identification numbers that are unique to each device.
When these devices are within 30 feet of each other, they automatically "find" and link to one another. You
don't have to worry about being connected to Bl
uetooth devices that you don't want to connect to: the device
requires that you confirm a connection before making it final. Up to eight Bluetooth
-
enabled devices can be
connected to each other in a piconet at any one time.

6.

Explain the difference between the terms
modulation
and
demodulation
. Which of these must a modem be
able to perform? Explain why.

On the sending end, the modem uses a process called
modulation
to transform the computer's digital signals
into analog
tones that can be conveyed through the telephone system. On the receiving end, the process used
is
demodulation
,

whereby the other modem transforms the signal from analog back to digital. Modems can
perform both modulation and demodulation

the name
modem
i
s short for modulator/demodulator
.