DLSoft Application Note12011

Barcodes generated using a barcode font do not scan

Problem
This is by far the most common problem encountered by technical support.
The conversation usually starts: " I typed some numbers into Word, changed 
the font to your barcode font and printed the barcode, but it won't scan".

Cause
Barcodes contain characters which are not visible in human readable form 
but which must be present in the barcode, and some barcode types do not 
translate single characters into single groups of bars. 

Resolutions
1. ALL barcodes must include the appropriate start and stop characters. For a 
small number of barcode types (Code 39, Code B and Codabar) that is all that 
is required. For other barcode types either a check digit is required, or the 
barcode data has to be translated into different characters in order to be 
displayed as a barcode using the ANSI/ASCII characters available in a font.

All dLSoft barcode products include tools that will translate data into a form
suitable for display in a barcode font, and these are described in the 
instructions that accompany each font.

2. Many barcode scanners are factory set to respond to specific barcode 
types, and may require the presence or absence of a check digit. These 
factory settings may usually be modified by scanning a set of barcode from
the pages of the scanner's instruction manual. 

If you cannot scan a particular barcode type you have produced you 
should check that (a) the scanner has recognition of that type turned ON,
and (b) whether you need to adjust the presence or absence of a check 
digit on either the scanner or the barcode.

3. Barcode scanners operate by detecting the sizes of the bars and 
spaces in a barcode image. Most printers attached to PCs have a 
resolution measured in dots per inch - and the bars produced by the 
printer can only be 1, 2, 3 etc. dots wide. Printing a barcode that is so 
small that the bars need to be one and a half dots wide will result in a 
barcode that will not scan. Try printing a larger barcode to see if that 
solves the problem.


Applies to
dLSoft Barcode Fonts for Windows (all types)
Aztec barcode font kit
DataMatrix barcode font kit
PDF417 barcode font kit
Universal barcode font kit.

dLSoft
Dec 2001