RJS Inspector D4000 Laser (FIRMWARE version A.05 and Earlier) - Manual (Page 53)

Operator ’ s Guide Appendix G
002-5568 RJS, Minneapolis, MN 47
Appendix G (ANSI Decodability)
ANSI Decodability Calculations
There is a specified method for calculating decodability for each symbol. But the method is generally
the same for all. Each element width in a barcode symbol should be consistent across the symbol.
Code 39
In the case of Code 39, two element widths are needed to produce a symbol.
For optimum scanning, each narrow element, whether a bar or space, should have the same
width dimension. And each wide element should have the same width dimension.
Simply stated, the Decodability grade indicates the amount of tolerance remaining in the width of
the most deviant element in the symbol. The more tolerance remaining, the higher the grade.
The grade is displayed showing both a calculated numeric and a letter grade, i.g. “D/bility
.90 A.”
UPC/EAN
In the case of UPC and EAN symbols, the grade is calculated per a proposed guideline draft
dated September 4, 1990 issued by the USS.
Decodability Grade Conversions
>= .62 = A
>= .50 = B
>= .37 = C
>= .25 = D
< .25 = F