In Code 93 barcodes, checksum validation enhances data accuracy by adding two check digits, “C” and “K.” Here’s a step-by-step guide to calculating these values:

1. Assign Numeric Values: Each character in the barcode has an assigned value from 0 to 47 (excluding start/stop characters).
2. Calculate the “C” Check Character: Start from the rightmost character, applying weights that repeat every 20 characters. Multiply each character’s value by its positional weight and sum the results. Divide the sum by 47, and the remainder provides the “C” character’s value.
3. Calculate the “K” Check Character: After calculating “C,” append it to the data and apply a similar calculation with weights repeating every 15 characters. The resulting remainder gives the “K” value.
   
   

This dual-check mechanism verifies data accuracy, reducing scanning errors.

Let’s look at an example to understand this better:

Suppose the data string for a Code 93 barcode is “ABC123”.

1. Assign Values: Each character corresponds to a value (A = 10, B = 11, C = 12, 1 = 1, 2 = 2, 3 = 3).
2. Calculate “C”: Starting from the right, apply weights from 1 up to 20, repeating as necessary:
   • A (10) 1 + B (11) 2 + C (12) 3 + 1 4 + 2 5 + 3 6 = Total Sum.
   • Divide this total by 47; the remainder is “C.”
3. Calculate “K”: Append “C” to the string and repeat with weights up to 15 for “K.”
   
   

This calculation ensures accurate barcode generation, reducing read errors.