Methods of Error Detection

Error checking is important in data transmission to ensure that data is received correctly and can be processed without issues.

Errors can occur due to interference in wired or wireless technology, such as signal degradation or electromagnetic interference.

Error detection methods include parity checks, which determine if the number of 1's in a byte matches the agreed parity, and checksums, which calculate a value based on the transmitted data to check for errors.

Parity checks can detect errors but do not pinpoint their location, while checksums determine if data has been corrupted but also do not reveal where the errors occurred.

Echo checks involve transmitting received data back to the sender to check for errors during transmission.

This text discusses various methods and algorithms used to detect errors in transmitted data.

One method mentioned is the use of parity bits, where a parity bit is added to each binary value to create 8-bit binary values. Odd or even parity is used to identify errors.

Another method discussed is the use of check digits, which are added to data blocks to determine if the data has been corrupted. Examples of check digits include ISBN numbers and barcodes.

The text provides walkthroughs of how check digits are calculated for ISBN numbers and barcodes.

A custom check digit algorithm in computer science is also mentioned, where a check digit byte is calculated based on the sum of all the bytes in a transmitted block of data.

The text also introduces the concept of Automatic Repeat Request (ARQ), which is a protocol used to notify the sender of errors in transmitted data and request retransmission if necessary.