Worth Data P11/12 MSI/Plessey Specifications, MSI Mod 10 check digit is calculated as follows

Appendix I

MSI/Plessey Specifications

Plessey is a variable length numeric only bar code. MSI Bar Code is a variable length, numeric-only code with an automatically appended Modulus 10 check digit. MSI is sometimes called Modified Plessey Code. If the user specifies an additional check digit, the MSI code can be 14 digits long, otherwise it has a maximum length of 13 characters. This is how the MSI check digit(s) are calculated:

The MSI Mod 10 check digit is calculated as follows:

The example bar code data is:

82345

1.Form a number from the odd positions, starting in the units position.

835

2.Multiply the new number by 2

(835)x 2 = 1670

3.Add the digits of product

1+ 6 + 7 + 0 = 14

4.Add the even digits of the original number to the result in 3

2 + 4 + 14 = 20

5.Subtract the result from the next highest multiple of 10

20 - 20 = 0

6.New Check Digit

0

7. Data with check digit is:

823450

I-1