RJS Inspector D4000 Auto Optic (FIRMWARE version A.05 and Earlier) - Manual (Page 58)

Appendix H Operator
’
s Guide
002-5564 RJS, Minneapolis, MN 51
Appendix H (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 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. 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. Grade “A” is the highest grade and grade “F” is lowest. (Even grade “F” is
decodable however.)
The grade is displayed in both its calculated numeric form and in its alphanumerical
equivalent (the ANSI specification numbered ANSI X3.182-1990).
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