2.2 Methods of Error Detection Cambridge IGCSE 0478

Why is error checking necessary after data transmission?

• To detect and correct errors that occur during transmission

• To reduce the size of transmitted data

• To speed up data transmission

• To convert data into binary before sending

Which of the following error detection methods adds a parity bit to data?

• Parity Check

• Checksum

• Echo Check

• ARQ

What is the purpose of a parity bit in error detection?

• To ensure that the total number of 1’s is even or odd

• To increase the speed of data transmission

• To encode data into hexadecimal format

• To replace corrupted data with random values

How does a checksum verify data integrity?

• The sender and receiver both calculate a checksum value to compare results

• The receiver sends the data back to the sender for confirmation

• The checksum converts data into a compressed format

• A special bit is added to every byte of data

In an echo check, how is data verified?

• The receiver sends the data back to the sender for comparison

• The data is checked using an even parity system

• The number of characters in the data is counted

• A random number is appended to the data

Where is a check digit commonly used?

• ISBN numbers and barcodes

• Email addresses and passwords

• Website URLs

• Computer file names

What happens in an Automatic Repeat Query (ARQ) when an error is detected?

• The receiver requests the sender to resend the data

• The receiver ignores the error and continues transmission

• The sender automatically deletes the corrupted data

• The receiver replaces the incorrect data with zeros

Which component of ARQ ensures that the sender retransmits data if no response is received?

• Timeout

• Parity Check

• Echo Check

• Checksum

What is the purpose of positive and negative acknowledgments in ARQ?

• To inform the sender whether the data was received correctly or not

• To encrypt data before transmission

• To detect and fix transmission errors automatically

• To count the total number of bytes sent

Which of the following is an example of a situation where ARQ would be used?

• Ensuring error-free data transmission over a network

• Compressing large files for storage

• Encoding an image file in hexadecimal format