This set of Data communication and Networking Multiple Choice Questions and Answers (MCQs) focuses on “Error Detection and Correction”.
PRACTICE IT NOW TO SHARPEN YOUR CONCEPT AND KNOWLEDGE
1. Reliable communication means that _______
- errors must be detected
- errors must be corrected
- noise must be eliminated
- a and b
D. 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
B. burst 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
A. single-bit 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
C. 18.5 microseconds
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
A. 500 kbps
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
B. parallel; serial
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
C. 300,000
8. Which of the following is an error detection method?
- multiplexing
- redundancy
- reciprocity
- conditioning
B. redundancy
9. Another name for VRC is _______
- LRC
- CRC
- checksum
- parity check
D. parity check
10. Which type of redundancy check do the upper layers primarily use?
- VRC
- CRC
- LRC
- checksum
D. 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
C. physical; data link
12. Checksum is an error detection method used primarily by the _______
- physical layer
- data link layer
- lower layers
- upper layers
D. upper layers
13. The most common and least expensive error detection mechanism is _______.
- VRC
- CRC
- LRC
- checksum
A. VRC
14. In the VRC method of error detection, redundancy consists of _______
- one data unit
- one bit
- one byte
- any of the above
B. one bit
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
C. 1s should be even
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
D. we cannot say
17. Which method can detect all single-bit errors?
- CRC
- VRC
- LRC
- all of the above
D. 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
D. 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
B. 16
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
B. 9
