Appendix C (Iso/Ansi Decodability); Iso/Ansi Decodability Calculations - RJS Inspector 5000 Operator's Manual

Operator's Guide Appendix C

Appendix C (ISO/ANSI Decodability)

ISO/ANSI Decodability Calculations

There is a specified method for calculating Decodability
for each symbology. But the method is generally the
same for all. Each element width in a bar code symbol
should be consistent across the symbol.
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. Each wide element should have the
same width dimension.
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). Grade 4.0 or "A" is the highest grade and grade
0.0 or "F" is lowest. (Even grade 0.0 or "F" may be
decodable).
The grade is displayed in both its calculated numeric
grade (ISO15416) and in its Letter grade (ANSI X3.182-
1990) equivalent.
ISO/IEC 15416:2016(E) implemented an interpolation
method as a way of reducing meaningless grade level
fluctuations when small changes in measurements cause
a grade to transition between grade levels.
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