Barcode Label Solutions Blog

Barcode 101

Posted by Susan Fields

Barcode 101 is an introduction to barcodes and barcode symbologies, which will be discussed in several blog posts.  You can also find more information in IntelliTech University.

What is a Bar Code?

A binary coding system, consisting of varying widths of vertical black lines (called bars) and white spaces, that when read by an optical scanner can be converted into machine language. Bars and spaces are just one of many "elements" that make up a bar code.

Elements of a Bar Code

Almost all bar codes contain the following elements:

Start and Stop Symbologies
At the beginning and end of some bar code symbologies, there are "start" and "stop" characters. These characters identify the symbology and also enable the scanner to read the symbol bidirectionally, and decode the data in the correct order. Bar codes generally include a check digit at the end that is based on an algorithm determined by the preceding characters. 

                                      Start and Stop


Quiet Zones
In order for the scanner to recognize the bar code, there must be a 1/4" wide area (next to the start and stop characters) that is void of any markings. If the space is not the correct length, the bar code symbol will not be read by the scanning device.

Quiet Zone 

Interpretation Line
The interpretation line is a series of human-readable characters which is usually located beneath the bar code.  An example is shown in the Code 128.

 

Interpretation Line

To be continued...

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