Data Communication and Networking – Error Detection and Correction MCQs

This set of Data communication and Networking Multiple Choice Questions and Answers (MCQs) focuses on “Error Detection and Correction”.
 

1
. Reliable communication means that _______
  • errors must be detected
  • errors must be corrected
  • noise must be eliminated
  • a and b
2
. If the ASCII "m" character is received as an "n" character, this is known as a _______
  • single-bit error
  • burst error
  • character error
  • byte error
3
. If the ASCII "7" character is received as the "5" character, this is known as a _______
  • single-bit error
  • burst error
  • character error
  • byte error
4
. If data were sent at 54 Kbps, what duration of noise would cause a single-bit error?
  • 54 microseconds
  • 5.4 microseconds
  • 18.5 microseconds
  • 18.5 milliseconds
5
. A 2-microsecond duration of noise caused a single-bit error. What is the minimum data rate?
  • 500 kbps
  • 50 kbps
  • 50 Mbps
  • 500 Mbps
6
. A single-bit error is more likely in a _______ transmission while a burst error is more likely in a _______ transmission
  • serial; parallel
  • parallel; serial
  • serial; multiplexed
  • duplex; parallel
7
. Data are being sent at 30 Mbps. An external electrical surge of 0.01 seconds affects the transmission. What is the maximum number of bits that can be affected?
  • 3000
  • 30,000
  • 300,000
  • 3,000,000
8
. Which of the following is an error detection method?
  • multiplexing
  • redundancy
  • reciprocity
  • conditioning
9
. Another name for VRC is _______
  • LRC
  • CRC
  • checksum
  • parity check
10
. Which type of redundancy check do the upper layers primarily use?
  • VRC
  • CRC
  • LRC
  • checksum
11
. VRC, LRC, and CRC are normally implemented in the _______ layer(s) for use in the _______ layer
  • upper; data link
  • network; data link
  • physical; data link
  • data link; physical
12
. Checksum is an error detection method used primarily by the _______
  • physical layer
  • data link layer
  • lower layers
  • upper layers
13
. The most common and least expensive error detection mechanism is _______.
  • VRC
  • CRC
  • LRC
  • checksum
14
. In the VRC method of error detection, redundancy consists of _______
  • one data unit
  • one bit
  • one byte
  • any of the above
15
. For even parity, after adding the redundant bit, the number of _______
  • 0s should be even
  • 0s should be odd
  • 1s should be even
  • 1s should be odd
16
. For even parity, after adding the redundant bit, the number of 0s _______
  • should be even
  • should be odd
  • should be less than the number of 1s
  • we cannot say
17
. Which method can detect all single-bit errors?
  • CRC
  • VRC
  • LRC
  • all of the above
18
. VRC can detect _______
  • all single-bit errors
  • burst errors if the number of errors is odd
  • burst errors if the number of errors is even
  • a and b
19
. If a block of bits contains eight data units with sixteen bits per data unit, how many bits is the LRC?
  • 8
  • 16
  • 17
  • 32
20
. If we use LRC for error detection on a block of bits containing eight data units with sixteen bits per data unit, how many total data units are sent?
  • 8
  • 9
  • 16
  • 32

 
 
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