Bar Code Verification

Questions Commonly Asked

1. Why do I need to verify my bar codes?
The most important reason is because customers demand quality bar codes! There are a number of industries which will initiate monetary fines for non readable bar codes.

2. What is the difference between verification and just scanning the bar code with any bar code scanner?
Verification guarantees the bar code you are printing will be able to be read (decoded) by all types of Scanners (Laser, Wand, CCD, etc.). Scanning only guarantees the scanner you are using will decode the bar code.

3. What is ANSI Verification?
ANSI verification refers to a bar code verification guideline (X3.182-1990 Annex A) published by the American National Standards Institute (ANSI). This mode of verification assigns a grade to a number of test parameters and an overall grade to the bar code, based on the lowest parameter grade. These grades are reflected in either A - F or 4 - 1. ANSI verification is geared to how well the bar code was decoded (read).

4. What is Traditional Verification?
Traditional Verification is the original form of electronic bar code verification. Traditional Verification is geared more toward how well the bar code is printed. Traditional verifiers will give you information regarding bar width deviation (bar growth and / or bar reduction), reflection, PCS and a number of other parameters.

5. What are the main parameters of ANSI and how do the grades correspond?

Minimum Reflectance (A or F)
Edge Determination (A or F)
Edge Contrast Minimum (A or F)
Reference Decode (A or F)
Symbol Contrast (A Through F)
Modulation (A Through F)
Defects (A Through F)
Decodability (A Through F)

Print Contrast Signal (PCS)
Reflectance Minimum (Rmn)
Reflectance Maximum (Rmx)
Ratio (When Applicable)
Check Digit (When Applicable)
Bar Width Deviation Graph
Inter Character Gap (ICG)
Quiet Zone (Clear Area) (QZ)

Reference Decode: Refers to whether the bar code was successfully decoded or not. If the Verifier was able to decode the bar code then the grade for this parameter would be an "A", if the bar code was not decoded successfully then the grade for this parameter would be an "F". It will be possible to get an "F" for Reference Decode" and still have all "A" for the remainder of the parameters since they are not dependent on a successful decode!

Decodability: This grade can be "A through F", and 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 will be. Simply stated Decodability refers to how even the bar code is printed, (X - dimension) are all the bars the same size or do the bars have bar growth or bar reduction across the entire length of the bar code.

9. What is "X Dimension"?
The nominal width of the narrow bars and spaces in a bar code.

10. What is "Z Dimension"?
The achieved width of the narrow elements, calculated as the average of the average narrow bar width and the average narrow space width.

11. What does ANSI stand for?
American National Standards Institute.

12. What does AIAG stand for?
Automotive Industry Action Group.

13. How do you determine what aperture size is needed on wand based verifiers?

For ANSI use the following chart:

For Traditional the rule of thumb is to use an aperture approximately 80% of the X dimension.

This technical explanation provided courtesy RJS Corporation.