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Check Digit

A check digit is an extra character appended to the end of a barcode whose value is derived from the sum (or weighted sum) of the values of the previous characters in the barcode. The Check Digit option enables you to specify whether or not check digits will be added to your barcodes.

Why Check Digits Are Used

Although automated data entry with a barcode reader is many times more reliable than manual data entry with a keyboard, the possibility of decoding errors can never be statistically eliminated. For example, a sudden jerk in a user's scanning motion or a printing defect in a barcode can cause a "substitution error" to occur. In situations where a substitution error might catastrophically affect the integrity of your database, the use of "check digits" is strongly recommended.

While check digits do not completely eliminate the possibility of substitution errors, they do reduce their likelihood even further, thereby improving data integrity.

How Check Digits Work

When a barcode reader that is configured to look for check digits scans a barcode which contains a check digit, it re-performs the same summation that was done by BarTender when the check digit was originally generated. The barcode reader then compares its computed check sum value with that of the check digit that was printed by BarTender. If the two values agree, the barcode reader transmits the barcode message. However, if the two values are different, the barcode reader knows that an error has occurred and no barcode characters are transmitted. The user must scan the barcode message again.

Symbology Specific Information for Check Digits

Several kinds of symbologies are always printed with check digits. Therefore, when these symbologies are specified for the currently selected barcode, the Check Digit option will be checked but grayed.

If the check digit that you want is unavailable, and you would like to append an additional check digit or define a custom check digit algorithm, you can do so by using VBScript. For more information, refer to Creating Custom Check Digits.

Supported Symbologies

This option is available for the following symbologies:

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