High Quality Content by WIKIPEDIA articles! In coding theory, Hamming(7,4) is a linear error-correcting code that encodes 4 bits of data into 7 bits by adding 3 parity bits. It is a member of a larger family of Hamming codes, but the term Hamming code often refers to this specific code that Richard W. Hamming introduced in 1950. At the time, Hamming worked at Bell Telephone Laboratories and was frustrated with the erroneous punched card reader, which is why he started working on error-correcting codes.