Introduction to barcode 

A striped world

Barcodes are everywhere and on just about everything these days but what are they for?

Bar coding was devised in the 1970's but has had a slow initial development and acceptance. However, twenty years later it has now become universal in its use and bar codes can be found everywhere.

What was first thought to be a novel system, rife with implications of Big Brother, and impossible to achieve, barcode systems are now a part of the "landscape" of commerce and, more generally, many organisations that need inventory and sales control, statistical insights, behavior patterns and other overviews.

Bar code run inventory and point of sale (POS) systems are common in most countries and it's hard to find a (packaged) product which does not have a barcode sticker or image on it somewhere. 

Bar code systems (see also our Barcode Systems page in this section) enables a strict sales and inventory control that was previously unattainable.

Taking the supermarket for example, a product which is sold is identified by its bar code at the checkout. This information is then sent to the cash register as well as to the inventory and administration.

The customer gets an itemised receipt of his purchases and the stores is able to keep a close watch on goods that are sold, going out of stock (inventory control) as well as provide information on consumer behavior (administration and statistics).

The store can then order new stocks automatically - depending on the level of automation and the software used - or generate a list for the sales staff and reports for the administration.

But bar codes aren't limited to supermarkets and retail stores. Libraries and other organisations are rapidly switching over to the bar code system to help them keep track of parts, parcels, member behaviour and other statistically relevant information.

The United States Postal Service, for example, adopted a bar code system (PostNet) to automatically sort its mail using high speed sorting machines, by assigning a bar code to each zip code and printing a bar code label on each letter or parcel.

Airports are now using bar code systems to handle their baggage systems in combination with sophisticated transport systems for automatic routing of baggage to the right plane.

Transport companies, such as national rail companies, print a bar code on their tickets to keep track of passenger preferences and movements. Shipping companies use bar code labels to track crates and containers and as well as their contents.

The future of barcodes

Science Fiction movies - such as Aliens 3 - show prisoners being bar coded in the neck, for example, so how far away is Big Brother really? Regardless of its social implications, however, it proves the practicality of bar coding.

What is a bar code?  

But what exactly is a bar code? What does it do and how is it put together?

Barcodes are basically a series of parallel lines, or bars, of varying width. The bars are usually black on a white background - but other colors can be used - and the width and number of bars can vary according to the type of bar code labeling system used. (See our Bar code Glossary page in this section for the different types of bar code systems.)

Most bar code systems use two different widths for the bars - thin and thick - but there are systems that employ four different widths.

The bars present bits - binary digits - with a value of either 0 or 1. This binary code is then converted by a computer to present the numbers 0 through 9.

Depending on the system the presence or absence of a bar, its width and its position, will give a bit value of either 0 or 1.

The number generated by the bar code is then assigned a product or item number. The system also works in reverse. Product or items numbers are assigned and a bar code label is generated and printed.

Most ordinary printers can handle bar code printing with some specific software and bar code sticker paper (see our Barcode Software page in this section) but there are printers specifically made for bar code label printing.

Reading the bar code label is done by a barcode scanner. This can be a handheld, wireless, or stationary scanner, equipped with an optical laser beam, which is moved across the code.

Connected to a computer and bar code system the information is passed on to the control software and an item is either added or subtracted from the stock, depending on the application.

Universal Product Code (UPC) and other bar code standards 

In the United States and other countries, a standard system of bar coding has been set up, called the Universal Product Code or UPC.

Primarily aimed at the food and retail industry the Universal Product Code provides a unique (bar code) number to each product or food type.

The bar code of the UPC system is divided into two parts. The five digits on the left identify a particular manufacturer and the five digits on the right identify a unique product made by that manufacturer.

But no single system remains the standard for long and there have been many other bar code systems devised since then for various uses and by many different organisations.

Examples are Datamatrix, Codes 39, 93 and 128, EAN-JAN bar code, Maxicode, MSI Plessey and PDF417.

2D and stacked bar codes can hold substantial amounts of data including whole databases within their coding.

For a list and short explanations of the various bar code systems and symbologies used please see our Barcode Glossary and Symbology page in this section.