The most common cause for a barcode font failing to scan
is a missing or incorrect start, stop or check digit. All barcode
fonts require a special start character, a stop character and most
require a calculated check digit. Make sure the required format
is being used to print the barcode fonts. Self-checking fonts like
can easily be entered from the keyboard with the start/stop characters
because a check digit is not required. For example to encode 123945 in a Code 39 barcode
font, enter *123945* in the application and select the Code 39 font
for that text. Some examples for encoding Codabar and Code 39 are
listed in this chart:
Because the checksum calculation can be complicated, IDAutomation
font tools and
encoders to calculate these characters. A correct barcode font
contains a start character, data characters, a check digit and a
stop character. All must be entered in this order to create a correct
The chart below contains a few examples for those fonts requiring
check digits. The "text required in barcode font" column may be
reproduced with any data in the
online font encoder.
Some demo and sample version fonts may be missing characters.
Make sure all demo and sample fonts are removed before installing
the fully functional versions. If the font name contains the
letter "S", it is usually a sample or demo font.
Code 128 and Interleaved 2 of 5 fonts distributed from July
2003 to January 2004 sometimes appear in the font list with the
in front of them. Choose the barcode fonts without the “@”
sign in the beginning of the font name because the
with the “@” sign may cause errors.
Browse to IDAutomation’s Online Barcode
Creator, select the correct symbology and enter some data
to encode. Print it out on the same printer. Does it scan? If not,
the problem is usually with the scanner. Make sure the symbology
is enabled in the scanner for the barcode being scanned; check the
minimum and maximum character settings; also check the scanner settings
for that symbology. Check the barcode scanner manual for reference.
Most barcode scanner manuals have test barcodes in them; try scanning
those of the same symbology to make sure they scan.
Try printing the barcode font at different point sizes. Not
all barcode scanners are the same; some lack the ability to scan
all types and sizes of barcodes. Some scanners have a narrow reading
width and cannot read long barcodes, while others cannot read small
barcodes. Review the readme file within the font distribution
ZIP file for the ranges of point sizes that can be used. Generally,
12 points is a good starting point. If that does not work, use 16
or 24 points.
All UPC and EAN fonts should be printed at 22 points or greater.
If the barcode appears to be truncated, increase the height
and width of the field the font is displayed in so there is extra
white space before and after the resulting barcode. Most barcodes
require a white space around the printed symbol that is at least
10 times the most narrow bar in the barcode.
Make sure the material the barcode is printed on has proper
contrast. Normally, the barcode should be black and the background
white. Using other colors will usually cause poor scanning conditions.
Also, make sure the material is not too glossy or the scanner light
may reflect and will not properly read the barcode.