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What is interference in data transmission?
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What is interference in data transmission?
Interference in data transmission is any disturbance that can cause errors in the data being sent, such as wire degradation or electrical fields changing the signal.
Define data loss.
Data loss is when some data is lost during transmission.
What is data gain?
Data gain is when additional data is received beyond what was originally sent.
Define data change.
Data change is when some bits in the transmitted data have been altered or flipped.
What can cause interference in wireless technology?
Interference in wireless technology can be caused by physical barriers (e.g. buildings, walls), bad weather (e.g. rain, clouds), or other wireless signals.
True or False?
Wired technology has less chance of causing an error than wireless technology.
False.
Wired technology carries more chance of causing an error as physical components can be damaged, degrade or receive interference from outside signals.
What is a format in computer science?
A format is a way of arranging data so that it can be easily understood by people and computers.
Why is it important to check for errors in data transmission?
It is important to check for errors in data transmission because computers expect data in certain formats, and if data is not as expected, things can go wrong.
Define corruption in data transmission.
Corruption in data transmission is when data received is not as expected and therefore is difficult or impossible to process.
What are two examples of date formats?
Two examples of date formats are DD/MM/YY (e.g. 13/04/14) and MM/DD/YYYY (e.g. 12/31/2020).
What is a parity check?
A parity check is a method to determine whether bits in a transmission have been corrupted.
Define parity bit.
A parity bit is a bit added to each byte transmitted to ensure the total number of 1's in the byte matches the agreed parity (odd or even).
What is the difference between odd and even parity?
Odd parity requires an odd number of 1's in the byte (including the parity bit), while even parity requires an even number of 1's.
True or False?
Parity checks can reveal where an error occurred in the data.
False.
Parity checks only check that an error has occurred, they do not reveal where the error(s) occurred.
What is a parity block?
A parity block is a block of data with the number of 1's totalled horizontally and vertically to check for errors and locate where they occurred.
Define parity byte.
A parity byte is a byte sent with the data which contains the parity bits from the vertical parity calculation in a parity block.
What is a checksum?
A checksum is a custom, user-created algorithm that performs mathematical calculations on data to determine if it has been corrupted.
How does an echo check work?
An echo check works by transmitting the received data back to the sender, who then checks the data to see if any errors occurred during transmission.
What is the main disadvantage of an echo check?
The main disadvantage of an echo check is that it isn't reliable as an error could have occurred when the sender transmits the data or when the receiver transmits the data back.
How does a checksum algorithm determine if an error has occurred?
A checksum algorithm determines if an error has occurred by calculating a checksum value before transmission, sending it with the data, recalculating it upon receipt, and comparing the two values. If they match, no error has occurred.
What is a check digit?
A check digit is a digit added to the end of a block of data to determine if the data has been corrupted.
Define ISBN.
ISBN (International Standard Book Number) is a unique identifier for books that includes a check digit for error detection.
How many digits are in a standard ISBN number?
A standard ISBN number has ten digits.
Where is the check digit located in an ISBN number?
The check digit in an ISBN number is the final digit.
What is a barcode?
A barcode is a series of black and white lines that can be scanned to identify an item, often including a check digit for validation.
What is the purpose of a check digit in a barcode?
The purpose of a check digit in a barcode is to validate and authenticate an item.
How are check digits calculated?
Check digits are calculated using custom, user-created algorithms that perform mathematical calculations on the data.
What is the main limitation of check digits?
The main limitation of check digits is that they can determine if data has been corrupted but do not reveal where the corruption occurred.
What does ARQ stand for?
ARQ stands for Automatic Repeat reQuest (or Query).
Define Automatic Repeat reQuest (ARQ).
Automatic Repeat reQuest (ARQ) is a protocol that notifies the sender that an error has occurred and that the data received is incorrect.
What is a negative acknowledgement transmission in ARQ?
A negative acknowledgement transmission in ARQ is a message sent by the receiver to indicate that the data is corrupted.
Define positive acknowledgement transmission in ARQ.
A positive acknowledgement transmission in ARQ is a message sent by the receiver to indicate that the data is correct.
What is a time-out in ARQ?
A time-out in ARQ is a certain time period that the sender waits before automatically resending the data if no acknowledgement is received.
True or False?
In ARQ, the process is repeated until all data has been received and acknowledged.
True.
In ARQ, the process is repeated until all data has been received and acknowledged.
What happens if the receiver doesn't send any acknowledgement in ARQ?
If the receiver doesn't send any acknowledgement in ARQ, the sender waits for a time-out period before automatically resending the data.
How does ARQ handle corrupted data?
ARQ handles corrupted data by having the receiver send a negative acknowledgement, prompting the sender to resend the data.
What is the main purpose of ARQ?
The main purpose of ARQ is to ensure accurate data transmission by detecting errors and requesting retransmission when necessary.
How does ARQ differ from other error detection methods?
ARQ differs from other error detection methods by actively requesting retransmission of corrupted data, rather than just detecting errors.