There’s nothing more frustrating when your barcode scanner or mobile computer won’t read a barcode.

There may be several reasons why a certain code cannot be decoded. Below is a list with some of the reasons a specific code may not be decoded. These are the more common reasons and should not be treated as a complete list.

 

The symbology is not enabled.

Determine the symbology of the bar code symbol and enable this symbology on the device (set-up). 

Determine if the device is setup to decode 2D barcode

 

The symbology is not supported.

Determine the symbology of the bar code and validate on the data sheet / user guide of the product that this symbology is supported. In the case that a symbology is not supported a different product is required to read this bar code.

 

The density of the code exceeds the product specification.

The density is identified by the X-dimension, which is the width of the smallest element (space or bar) in the bar code. Check what the mil size of the bar code is. Validate on the datasheet of the product that the mil size supported for this symbology is equal to or smaller than the mil size of the bar code. For devices equipped with an imager decoder, there are often different image engines available with different x-dimension specifications (see the datasheet for details). In the case that the mil size of the bar code is smaller than the mil size specified on the datasheet, then a different product is required to read this bar code.

 

The width of the bar code exceeds the scan view / laser beam.

On the datasheet the Scan Angle / Skew Angle and the Depth of Field for the mil size are specified. With this information the maximum width that can be seen by the scan engine can be calculated. When this calculated width is far less than the actual size of the bar code a different product is required to read this bar code.

 

The bar code print quality is too poor.

The following issues related to the bar code quality are some of the more common:

 

  • Use of a certain background color (bad contrast between bars and spaces).
  • Use of a certain color or fainted black color for the bars (bad contrast between bars and spaces).
  • The bar code does not allow adequate space to the left or right of the code on the label (inadequate Quiet Zone).
  • Missing a portion of the bar code / not enough elements (the visible bars and spaces do not create the correct code).
  • The bar-width and or space-width is incorrect or inconsistent throughout the symbol (dimensional errors)

 

The cable and scanner are mismatched.

Some scanner models support multiple interfaces such as USB and RS232, but not on the same scanner. Confirm that the scanner and cable work together. 

 

Device has a hardware defect.

Device needs to be sent in for repair.