Barcode Education

The most common bar codes are symbols consisting of a series of bars and spaces which can be applied to packages, cartons, bottles, and other commercial products. The bars and spaces in each symbol are grouped in such a way to represent a specific ASCII character. The interpretation of these groups is based on a particular set of rules called symbologies. Various symbologies have been developed for particular applications. Some examples are shipping and receiving, manufacturing, retail, healthcare, transportation, document processing and tracking, and libraries.

Currently there are more than 400 symbologies in use. Some are alphanumeric, while others contain the full ASCII set, or only numeric data. When deciding on a particular bar code, it is best to use a universal symbology that is supported by most manufacturers. In addition, one must consider the type and amount of data to be encoded, as well as the scanning and printing equipment.

Each character in a bar code is represented by a series of bar and spaces. Typically, the code includes a quiet zone, start code, data, stop code, and a trailing quiet zone. Some symbologies support check digits to ensure data integrity. If this is supported, the check digit(s) is usually before the stop code.