Bar Code Overview

Since their invention in the early 1950s bar codes have accelerated the flow of products and information throughout the global business community. Coupled with the improvements in data accuracy that accompanies the adoption of bar code technology over keyboard data entry, bar code systems are critical elements in conducting business in today’s global economy. Bar code technology encompasses the symbologies that encode data to be optically read, the printing technologies that produce machine-readable symbols, the scanners and decoders that capture visual images of the symbologies and convert them to computer-compatible digital data, and the verifiers that validate symbol quality.

There are many different bar code symbologies, or languages. Each symbology has its own rules for character (e.g. letter, number, punctuation) encodation, printing and decoding requirements, error checking, and other features.

The various bar code symbologies differ both in the way they represent data and in the type of data they can encode: some only encode numbers; others encode numbers, letters, and a few punctuation characters; still others offer encodation of the 128-character, and even 256-character, ASCII sets. The newest symbologies include options to encode multiple languages within the same symbol; allow user-defined encodation of special or additional data; and can even allow (through deliberate redundancies) reconstruction of data if the symbol is damaged.

At the last count, there were about 225 known bar code symbologies but only a handful of these are in current use and fewer still are widely used.