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B227 Data Communications
Quiz 1 2001
Directions
You are required to place you answers on a computer readable answer
sheet. Hand your completed sheet in at the end of the quiz.
Remember! Place your name and student No. on the answer sheet.
KEEP YOUR EYES ON YOUR OWN PAPER!!!
1.
a)
b)
c)
d)
are rules that govern a communication exchange.
Media
Criteria
Protocols
all of the above
2. Frequency of failure and network recovery time after a failure are measures of the
a network.
a) performance
b) reliability
c) security
d) feasibility
of
3. The performance of a data communications network depends on
a) the number of users
b) the transmission media
c) the hardware and software
d) all of the above
4. Viruses are a network
a) performance
b) reliability
c) security
d) all of the above
issue.
5. Which organization consists of computer scientists and engineers and is known for its
development of LAN standards?
a) EIA
b) ITU-T
c) ANSI
d) IEEE
6.
is the division of one task among multiple computers.
e) Distributed processing
f) Distributed massaging
g) Distributed telephony
h) Electronic massaging
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B227 Data Communications
Quiz 1 2001
7. If a protocol specifies that data should be sent at 100 Mbps, this is a
a) syntax
b) semantics
c) timing
d) none of the above
issue.
8. When a protocol specifies that the address of the sender must occupy the first four
bytes of a message, this is a
issue.
e) syntax
f) semantics
g) timing
h) none of the above
9. When a protocol specifies that the address of the sender means the most recent
sender and not the original source, this is a
issue.
a) syntax
b) semantics
c) timing
d) none of the above
10. What is the main difference between a de facto standard and a de jure standard?
a) A de facto standard has been legislated by an officially recognized body; a de
jure standard has not.
b) A de jure standard has been legislated by an officially recognized body; a de
facto standard has not.
c) The inventing company can wholly own a de jure standard and not a de facto
standard.
d) A de jure standard is proprietary; a de facto standard is not.
11. Which topology requires a central controller or hub?
a) mesh
b) star
c) bus
d) ring
12. Communication between a computer and a keyboard involves
a) simplex
b) half-duplex
c) full-duplex
d) automatic
13. A
a)
b)
c)
d)
transmission.
connection provides a dedicated link between two devices.
point-to-point
multipoint
primary
secondary
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B227 Data Communications
14. In
Quiz 1 2001
transmission, the channel capacity is shared by both communicating
devices at all times.
a) Simplex
b) half-duplex
c) full-duplex
d) half-simplex
15. MacKenzie Publishing, with headquarters in London and branch offices throughout
Asia, Europe, and South America, is probably connected by a
.
a) LAN
b) MAN
c) WAN
d) none of the above
16. BAF Plumbing has a network consisting of two workstations and one printer. This is
most probably a
.
a) LAN
b) MAN
c) WAN
d) none of the above
17. A cable break in a
a) mesh
b) bus
c) star
d) primary
topology stops all transmission.
18..A network that contains multiple hubs is most likely configured in a
a) mesh
b) tree
c) bus
d) star
19. The OSI model consists of
a) three
b) five
c) seven
d) eight
20. The
a)
b)
c)
d)
layers.
layer decides the location of synchronization points.
transport
session
presentation
application
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topology.
B227 Data Communications
Quiz 1 2001
21. The end-to-end delivery of the entire message is the responsibility of the
a) network
b) transport
c) session
d) presentation
22. The
a)
b)
c)
d)
layer is the layer closest to the transmission medium.
physical
data link
network
transport
23. In the
a)
b)
c)
d)
physical
data link
network
transport
layer.
layer, the data unit is called a frame.
24. Decryption and encryption of data are the responsibility of the
a) physical
b) data link
c) presentation
d) session
layer.
25. As the data packet moves from the upper to the lower layers, headers are
a) added
b) removed
c) rearranged
d) modified
.
26. When data are transmitted from device A to device B, the header from A’s layer 5
is read by B's
layer.
a) physical
b) transport
c) session
d) presentation
27. The
a)
b)
c)
d)
layer changes bits into electromagnetic signals.
physical
data link
transport
presentation
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28. The
a)
b)
c)
d)
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layer can use the trailer of the frame for error detection.
physical
data link
transport
presentation
29. The physical layer is concerned with the transmission of
medium.
a) programs
b) dialogs
c) protocols
d) bits
over the physical
30. Which of the following is an application layer service?
a) network virtual terminal
b) file transfer, access, and management
c) mail service
d) all of the above
31. In a time-domain plot, the vertical axis is a measure of.
a) amplitude
b) frequency
c) phase
d) time
32. As frequency increases, the period
a) decreases
b) increases
c) remains the same
d) doubles
.
.
33. A sine wave is
.
a) periodic and continuous
b) aperiodic and continuous
c) periodic and discrete
d) aperiodic and discrete
34. If the baud rate for a QAM signal is 1800 and the bit rate is 9000, how many bits are
there per signal element?
a) 3
b) 4
c) 5
d) 6
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35. Which conversion type needs sampling of a signal?
a) digital-to-digital conversion
b) analog-to-digital conversion
c) digital-to-analog conversion
d) all of the above
36. Modulation of an analog signal can be accomplished through modulation of the
the carrier signal.
a) amplitude
b) frequency
c) phase
d) any of the above
37. Transmission media are usually categorized as
e) fixed or unfixed
f) guided or unguided
g) determinate or indeterminate
h) metallic or non-metallic
38.
a)
b)
c)
d)
.
cable consists of an inner copper core and a second conducting outer sheath.
Twisted-pair
Coaxial
Fiber-optic
Shielded twisted-pair
39. At the lower end of the electromagnetic spectrum we have
a) radio waves
b) power and voice
c) ultraviolet light
d) infrared light
40.
of
.
are the highest frequency electromagnetic waves in use for data communications.
a) Visible light waves
b) Cosmic rays
c) Radio waves
d) Gamma rays
41. Smoke signals are an example of communication through
a) a guided medium
b) an unguided medium
c) a refractive medium
d) a small or large medium
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B227 Data Communications
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42. In an optical fiber, the inner core is
a) more dense than
b) less dense'than
c) the same density as
d) another name for
43. In
a)
b)
c)
d)
.
propagation, low-frequency radio waves hug the earth.
surface
tropospheric
ionospheric
space
44. If a satellite is in geosynchronous orbit, it completes one orbit in
a) one hour
b) 24 hours
c) one month
d) one year
.
45.
is a type of transmission impairment in which the signal loses strength
due to the resistance of the transmission medium.
a) Attenuation
b) Distortion
c) Noise
d) Decibel
46.
is a type of transmission impairment in which the signal loses strength
due to the different propagation speed of each frequency that makes up the signal.
a) Attenuation
b) Distortion
c) Noise
d) Decibel
47.
is a type of transmission impairment in which an outside source such as
crosstalk corrupts a signal.
a) Attenuation
b) Distortion
c) Noise
d) Decibel
48. The performance of transmission media can be measured by
a) throughput
b) propagation speed
c) propagation time
d) all of the above
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B227 Data Communications
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49. Error detection is usually done in the
a) physical
b) data link
c) network
d) any of the above
layer of the OSI model.
50. Which error detection method involves polynomials?
a) VRC
b) LRC
c) CRC
d) checksum
51. Which of the following best describes a single bit error?
a) A single bit is inverted.
b) A single bit is inverted per data unit.
c) A single bit is inverted per transmission.
d) any of the above
52. Which OSI layer corresponds to the TCP-UDP layer?
a) Physical
b) Data link
c) Network
d) Transport
53. Which OSI layer corresponds to the IP layer?
a) Physical
b) Data link
c) Network
d) Transport
54. Which OSI layer(s) correspond to TCP/IP’s application layer?
a) Application
b) Presentation
c) Session
d) All of the above
55. The data unit in the TCP/IP data link layer is called a
a) Message
b) Segment
c) Datagram
d) Frame
End of Quiz
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