HP 3000 Manuals HP 3000 Manuals
ALPHABETIC CHECK DIGITS
Letters of the alphabet are treated like numbers in either modulus 10 or
modulus 11 check digit calculations. This is done by assigning a digit
to each letter of the alphabet as follows:
A B C D E F G H I J K L M N 0 P Q R S T U V W X Y Z ( =space)
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 0
A value to be checked may be preceded by a plus or minus sign; however,
the sign is ignored in the check digit calculations. To illustrate,
perform a modulus 10 check digit calculation on a value that contains
letters as well as numbers:
Assume a basic value 3 4 G 1 2 H
Change the letters to digits 3 4 7 1 2 8
Multiply alternate digits by 2 8 2 16
Digits not multiplied 3 7 2
Sum with digits that were not multiplied 3+8+7+2+2+1+6 = 29
Subtract sum from next higher number ending 30-29 = 1
with zero
Check digit = 1
Self-checking number 34G12H1