Automated Data Collection Technology is used to enter information into a business computer system. Here machine readable bar code symbols are used to increase the speed and accuracy of collected data. Bar Codes are graphical representations of information encoded within a defined pattern of alternate-width dark bars and white (blank) spaces representing numbers or characters.

The first three digits in the bar code are the country codes. eg. 890 for India. The next four digits are allotted to each manufacturer. The next five digits are the product code. It allows for 1,00,000 different products to have separate codes from 00000 to 99999. The last digit is the check digit which is calculated by using the previous 12 digits.

The lines within a bar code are called "bars". The spaces and the area around the bars, which are usually white or a light color, are known as "quiet zones". Each bar code is unique. This unique arrangement of the bars and spaces is referred to as a "bar code symbology" or "bar code format". Since bar codes are designed to suit specific business applications, they vary in size, shape and data content.

The components of a bar code

Country Code: Each country is identified by a specific country code. For e.g.: India's country code is 890
Check Digit: This is the checksum, or error checking digit that is automatically calculated from the previous 12 digits.
Manufacturer Number: These characters represent the manufacturer's code, which is assigned to each manufacturer by EAN India.
Product Code: These characters encode the item's unique identification number.
Center Guard Bars: These two longer bars divide the two halves of the code.

Initially, the use of bar code technology was confined to traditional manufacturing and distribution businesses. Now, with the advent of the personal computer and the introduction of point-of-sale (POS) terminals at local supermarkets, the use of bar codes has become increasingly popular.

Some Bar coding Applications:

In manufacturing units, to track work in progress and provide real time production information.

In retail stores, the use of item inventory number in bar code form allows for quick inventory via a portable barcode reader. To track documents. Bar code labels are
affixed to each case folder.

This permits a folder's movement to be tracked, making it easy to accurately identify the present location of all active files.

To validate security routes. Specific check points are labeled with bar code tags.
The security guard carries a compact portable bar code reader and at each check point, the location tag is scanned and the date/time automatically recorded.

Library cards use bar coded ID cards for fast, accurate sign-out.

Many rental companies issue bar coded cards to their regular customers for the same reason.

Hospital patients have bar coded wrist tags.

Now they are being used to tag birds and insects for research studies.

In direct mail marketing, mailers are often sent out with bar coded information which can include the date of the mailing, the source of the mailing list used, which of several test pieces was sent, etc.