Error Correction and Substitution Detection
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-03
A multi-digit number is provided with an error correction digit and a substitution detection digit which enhance the ability of an automatic reading system to reliably read the number. The error correction digit permits computation of any single digit in the number which is found unreadable by the automatic reading system. The substitution test digit verifies that the digits read by the automatic reading system have been correctly identified. The error correction digit (ECD) is computed by a decimal addition of all digits, retaining only the units digit. Example: Record 004624397742148693701796 Result of decimal add = 109 ECD = 9 The substitution detection digit (STD) is computed by a decimal addition, with 1,2,1 weighting, retaining only the units digit.