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Chapter 08 Data and
Network Communication Technology
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1. Messages can be loosely categorized into two types—data
messages and command messages.
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2. Data messages vary in format and content and can include
any primitive CPU data types or more complex data types.
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3. Sender and received can use different methods of
encoding, transmitting, and interpreting the bits of a message.
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4. Command messages can be used to transmit information
about data messages, such as format, content, length, and other information
the receiver needs to interpret the data message correctly.
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5. Communication protocols are less important for
computer-to-computer communication than for person-to-person communication.
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6. A complete communication protocol is a complex
combination of subsidiary protocols and the technologies to implement them.
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7. Bits are encoded in a wave by precisely manipulating,
or modulating, amplitude, frequency, or phase.
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8. The FM method holds frequency constant while varying
amplitude to represent data.
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9. Phase is a wave characteristic that’s fundamentally the
same as amplitude or frequency.
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10. Square waves are the preferred method of transmitting
digital data over short distances, such as on a system bus.
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11. Wave characteristics, such as frequency and amplitude,
are inherently discrete.
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12. S/N ratio is computed as the log of signal power minus
noise power.
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13. RF transmission is more complex than wired transmission
because it incorporates more sophisticated error detection/correction and
security methods.
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14. Communication line cost is the same in simplex and
half-duplex modes.
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15. A parallel channel’s transmits individual bits over
separate wires, fibers, or frequencies.
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16. To limit skew errors, high-speed parallel
communication channels must be short, typically less than two meters.
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17. In the server arena, serial standards, such as Serial
Attached SCSI (SAS), have replaced older parallel standards.
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18. Circuit switching makes efficient use of channel
capacity in most data transmission situations.
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19. Circuit switching is inefficient for most data
transmission settings because few users require high data transmission
capacity continuously.
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20. Despite its complexities, packet switching is the
dominant form of intercomputer communication.
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21. Under FDM, a single narrowband channel is partitioned
into multiple broadband subchannels.
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22. Narrowband channels in a single broadband channel must
use the same signaling methods, communication protocols, and transmission
speeds.
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23. Because block size is always the same in synchronous
transmission, the receiver always knows where one block ends and another
begins.
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24. Asynchronous transmission uses channel capacity more
efficiently than synchronous transmission.
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25. A crucial component of any communication protocol is a
method for detecting and correcting errors in data transmission, reception,
or interpretation.
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26. Parity checking can be based on even or odd bit
counts.
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27. Parity checking has a low Type I error rate.
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28. Type I error rates can be reduced by combining parity
checking and block checking.
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29. CRC has much higher Type I and Type II error rates
than parity and block checking.
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30. Unlike block checking, CRC cannot produce a BCC for a
group of characters or bytes.
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31. A ____ message contains instructions that control some
aspect of the communication process.
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32. A complete ____ of a sine wave follows its full range
from zero to positive peak, back to zero, to its negative peak, and then back
to zero again.
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33. ____ is a specific time point in a wave’s cycle.
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34. ____ is the number of cycles occurring in one second
and is measured in hertz (Hz).
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35. A(n) ____ is a data transmission event or group of
events representing a bit or group of bits.
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36. ____ represents bit values as specific wave
amplitudes.
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37. Amplitude modulation is sometimes called ____.
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38. ____ represents bit values by varying carrier wave
frequency while holding amplitude constant.
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39. Frequency modulation is also called ____.
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40. ____ is a technique for embedding multiple bit values
in a single wave characteristic, such as frequency or amplitude.
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41. Square waves can be generated by rapidly switching (pulsing)
an electrical or optical power source—a technique called ____.
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42. ____ routes signals between two locations through a
physical connection, such as copper wire or optical fiber.
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43. The term ____ describes transmissions using
frequencies between 50 Hz and 1 terahertz (THz).
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44. The term ____ describes the maximum number of bits or
bytes per second that the channel can carry.
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45. The term ____ describes the maximum number of bits or
bytes per second that the channel actually achieves with a specific
communication protocol.
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46. Noise can be introduced into copper, aluminum, and
other wire types by ____.
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47. In a communication channel, ____ refers to unwanted
signal components added to the data signal that might be interpreted
incorrectly as data.
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48. As bit transmission speed is increased, the duration
of each bit in the signal, known as the ____, decreases.
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49. The most common wired transmission media for LANs is
____ cable.
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50. ____ is the most expensive cable type
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51. ____ cable can be constructed of glass or plastic.
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52. ____ cable uses fibers that vary continuously in
diameter from center to edge.
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53. In a single electrical communication channel, a(n)
____ wire carries data and the return wire completes the electrical circuit.
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54. In a single communication channel a ____ wire
completes an electrical circuit between sending and receiving devices.
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55. In ____ mode, messages flow in only one direction
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56. ____ mode uses a single shared channel, and each node
takes turns using the transmission line to transmit and receive.
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57. In ____ mode, the receiver can communicate with the
sender at any time over the second transmission line, even while data is
still being transmitted on the first line.
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58. ____ transmission uses a separate transmission line
for each bit position.
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59. ____ is noise added to the signal in the wire from EMI
generated by adjacent wires.
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60. Most local phone service is based on a channel-sharing
strategy called ____.
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61. ____ describes techniques for splitting data transfer
capacity into time slices and allocating them to multiple users.
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62. Long-distance telecommunication providers use FDM to
multiplex single-mode optical fibers, an application commonly called ____.
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63. ____ is a high-speed communication architecture
intended to interconnect devices such as servers, secondary storage
appliances, and network switches.
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64. ____ are used by devices such as general-purpose
servers that can initiate and respond to data transfer requests.
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65. In synchronous transmissions, messages are transmitted
in fixed-size byte groups called ____.
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66. ____ have a predetermined pattern of signal transitions
designed for easy clock synchronization.
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67. Asynchronous transmission adds one or more ____ bits
to the beginning of each message.
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68. With ____ parity, the sender sets the parity bit to 0
if the count of 1-valued data bits in the character is odd.
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69. Parity checking can be expanded to groups of characters
or bytes by using ____.
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70. ____ is the most widely used error-detection
method.
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71. A(n) ____________________ is a unit of data or
information transmitted from a sender to a recipient.
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72. A(n) ____________________ is a set of rules and
conventions for communication.
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73. Light, radio frequencies, and electricity travel
through space or cables as a(n) ____________________.
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74. ____________________ is a measure of wave height or
power—the maximum distance between a wave’s peak and its zero value.
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75. The ____________________ of a sine wave is measured in
degrees, with 0° representing the beginning of the wave’s cycle and 360°
representing the end.
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76. A wave with encoded bits is called a(n)
____________________ wave because it transports bits from one place to
another.
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77. A(n) ____________________ signal uses the full range
of a carrier wave characteristic to encode continuous data values.
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78. A(n) ____________________ signal can contain one of a
finite number of possible values.
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79. A(n) ____________________ consists of a sending
device, a receiving device, and the transmission medium connecting them.
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80. The communication path that transports signals is
called a(n) ____________________.
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81. The difference between a signal’s maximum and minimum
frequencies is called the signal ____________________.
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82. A(n) ____________________ signal is created by
combining multiple simple signals.
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83. ____________________ is the reduction in signal
strength (amplitude) caused by interactions between the signal’s energy and
the transmission medium.
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84. The term ____________________ refers to changes to the
data signal caused by interaction with the communication channel.
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85. ____________________ cable is the most common
transmission medium for phone and local area network (LAN) connections.
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86. ____________________ cable contains a single copper
conductor surrounded by a thick plastic insulator, a metallic shield, and a
tough plastic outer wrapping.
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87. ____________________ transmission is more complex than
wired transmission because it incorporates more sophisticated error
detection/correction and security methods.
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88. ____________________ distortion creates echoes that
blur or smear signal content, increasing the error rate
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89. In half-duplex mode after sending a message, the first
node signals its intent to cease transmission by sending a special control
message called a(n) ____________________.
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90. ____________________ mode allows the receiver to
request retransmitting a message if it detects errors.
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91. ____________________ transmission uses only a single
transmission line and a return wire.
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92. Packet switching, the most common type of TDM, divides
messages from all users or applications into small pieces called
____________________.
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93. ____________________ transmission ensures that sender
and receiver clocks are always synchronized by sending continuous data
streams.
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94. In ____________________ transmission, messages are sent
on an as-needed basis.
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95. Under ____________________ parity, the sender sets the
parity bit to 0 if the count of 1-valued data bits is even or to 1 if the count
of 1-valued data bits is odd.
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96. What are the three characteristics of sine waves that
can be manipulated to represent data?
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97. Why are waves important in communication?
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98. Describe some options regarding light transmission in
communication technology.
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99. What are the two main synchronization problems that
can occur during message transmission?
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100. List two characteristics in which error detection and
correction methods vary.
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