This document discusses error detection and correction codes. It describes how errors can occur during digital data transmission and how extra bits are added to data to detect and sometimes correct errors. There are two types of errors: single bit errors, where one bit is changed, and burst errors, where multiple consecutive bits are changed. Error detection codes can detect errors, while error correcting codes can detect and correct errors. Common error detection techniques include parity bits and cyclic redundancy checks. Hamming codes provide error detection and correction by using parity bits located at specific bit positions to identify the location of errors.