This troubleshooting procedure assumes the barcode font is installed and can be printed from an application (such as WordPad in Windows). If the font does not print from an application, refer to the Font Installation Procedures or TrueType font problems in Windows.

1. 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 Code 39 and Codabar 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 of encoding Codabar and Code 39 are listed in this chart:

   Barcode type	Data to encode in barcode	Text required in barcode font
   Code 39	123945	*123945*
   Code 39	TEST 3OF9	*TEST=3OF9*
   Codabar	123945	A123945B

   Because the checksum calculation can be complicated, IDAutomation provides several Font 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 barcode.
   The chart below contains a few examples of those fonts requiring check digits. The “text required in barcode font” column may be reproduced with any data in the online font encoder.

   Barcode type	Data to encode in barcode	Text required in barcode font
   Code 128 (auto mode)	Code 128456	ÌCodeÂÇ,tXXÎ
   DataBar	12345678901231	a1a3a1b1f1b3h1a1d1a5a1a2a1c2b2b1a9c1a2a2c3c1a1
   EAN-8	2345678	(2345*QRSP(
   EAN-13	102900384756	V(02J0AD*SORPQP(
   Interleaved 2 of 5	23456789	Ë8NdzÌ
   MSI	748030002	(7480300024)
   Postnet or Planet	72293384756	(722933847564)
   UPC-A	10290038475	V(b02900*NSORPl(V
   UPC-E	07830000034	U(HI3D43)V

2. 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.
3. Code 128 and Interleaved 2 of 5 fonts distributed from July 2003 to January 2004 sometimes appear in the font list with the @ sign in front of them. Choose the barcode fonts without the “@” sign at the beginning of the font name because the font names with the “@” sign may cause errors.
4. 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.
5. 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.
6. 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.
7. Check the print quality and DPI of the printer. Thermal printers that are 203dpi or less can produce poor quality problems if not used properly.
8. Make sure the material the barcode is printed on has the 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.