Example of barcode parameters

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Let’s say a customer provides the following documentation describing their barcodes.

We use a codabar barcode format, which uses a modulus 11 check digit.
The barcode format is the same for both borrowers and items — a 6 digit running number, with the 7th number being the check digit.
Borrowers have a prefix of A5/ and a suffix of A.
Items have a prefix of B5/ and suffix D.

In this example we’ll be using a MOD11 check digit. This uses a modulus 11 check digit with declining weights for verification of accuracy. The formula for verifying the barcode number employs a declining multiplier as follows:

Multiply the 1st digit (leftmost) by 7 and store the result.
Multiply the 2nd digit by 6 and add the result to the previous total.
Multiply the 3rd digit by 5 and add the result to the previous total.
Multiply the 4th digit by 4 and add the result to the previous total.
Multiply the 5th digit by 3 and add the result to the previous total.
Multiply the 6th digit by 2 and add the result to the previous total.
Divide the total by 11 and store the remainder.
Subtract the remainder from 11. The result must equal the 7th digit.

For example, to get the number 1573969 (where the last “9” is the check digit):

(1*7) = 7

(5*6) = 30

(7*5) = 35

(3*4) = 12

(9*3) = 27

(6*2) = 12

So 7 + 30 + 35 + 12 + 27 + 12 = 123.

123 / 11 = 11, remainder 2. Therefore the check digit = 9 (i.e., 11 - 2).

If the remainder equals zero, the check digit equals zero. If the remainder equals 1, then the customer wants to use a dash “-” as the check digit.

So, let’s say we have a borrower barcode A5/1573969A. The barcode parameters required to describe this particular barcode would be:

Comment	Borrower card
Enable barcode	Yes
Leading characters	A5/
Strip leading	No
Trailing characters	A
Strip trailing	No
Min. length	11
Max. length	11
Check digit type	$BCD_CDMOD11$-$
Check range start position	4
Check range length	6
Check digit start position	10
Check digit length	1
Remove check digit	No
Pre-processing routine
Filter
Trim blanks	No

The leading characters A5/ and trailing character A are used to identify the barcode type leading and trailing characters, and are NOT stripped. The Check range start position/length and Check digit start position/length are required to specify the part of the barcode over which the check digit is calculated.

In this example, the customer wants to use a dash “-”rather than the usual “X” if the check digit is 10. Therefore we’ve specified the Check digit type as $BCD_CDMOD11$-$ rather than BCD_CDMOD11.