| code according to which a larger number of characters, symbols or signal elements than strictly necessary are used to represent information
EXAMPLE Error detecting code; error correcting code.
Note 1 to entry: In telegraphy, a five-unit code using all the characters of International Telegraph Alphabet No. 2 is not redundant. A seven-unit code such as International Telegraph Alphabet No. 3 which uses only signals made of four elements of A condition and three elements of Z condition is redundant.