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1. What is bar code technology? Bar code is the predominant automatic identification technology used
to collect data about any person, place, or thing. Bar codes work much
like Morse Code, in which patterns of dots and dashes represent letters
and numbers. Unlike Morse Code, however, information in bar codes is symbolized
by bars and the space separating the bars, which vary by thickness and
location, depending on the type of symbology. Bar code readers actually
read the space between the bars.
The "quiet zone" is the area on a bar code that is free of any printing preceding the first bar (start character) and following the last bar (stop character). The minimum size of the quiet zone is ten times the narrowest element (bar or space). The "wide to narrow ratio" is the ratio of dimensions between wide elements and narrow elements. The dimension of the narrow bars and spaces is called the "X" dimension. The dimension of the wide bars and spaces is a multiple of "X". The ratio is preselected according to the symbology and must be consistently maintained. How do I know which bar code symbology to use? Choosing the correct symbologies can be as easy as knowing which symbology is used in your industry. If your needs are unique to your company or for strictly internal use, you will need to decide which will work best for your application. Each symbology has a different specification such as the type of information that can be encoded (alpha, alphanumeric, numeric only, lower/upper case alpha character, and other symbols). Some symbologies include check digits for security, and others are more appropriate for smaller spaces due to density by the bar code. For years bar codes have been promoted as a machine readable license plate. Each label contained a unique serial number coded in black and white bars that was a key into a database containing detailed information. However, many end users wanted to code more information. They wanted the bar code to be a portable database rather than just a database key. Unlike a typical bar code which stores information vertically, a 2-D or two-dimensional bar code stores information both vertically and horizontally. A 2-D bar code not only is capable of storing more data, it also helps to reduce the possibility of data being misread. The first truly two-dimensional bar code, called Code 49, was introduced by Intermec Corporation in 1988. Since Code 49's introduction, six others have either been invented or have been redesigned to meet the need to place a portable database in as little space as possible. More recently, the ability to encode a portable database has made two-dimensional symbologies attractive in applications where space is not at a premium. One example is storing name, address, and demographic information on direct mail business reply cards. A good direct mail response is often less than two percent. If the return card is only coded with a "license plate" (ordinary bar code), the few replies much be checked against a very large database, with possibly millions of names. This can be quite expensive in computer time. If all the important information is printed in two-dimensional code at the time the mailing label is printed, there is very little additional cost, and a potential for great savings when the cards are returned. There are over 20 different 2-D symbologies available today.
The various forms of bar codes have evolved over time as the bar code has become more commonly used. The original bar codes were shaped like a bullseye so they could be read from any angle. Later, a straight version was used instead, but the early forms of bar code were not capable of encoding letters. To meet the needs of companies that wanted to encode alphanumeric data, new bar codes were invented that were capable of encoding letters, numbers, and punctuation marks. The Universal Product Code (UPC) is generally used in the retail industry. Interleaved 2 of 5, Code 39, and Code 128 are used for mostly industrial applications. The different symbologies are differentiated by their character sets (numeric only versus alphanumeric), by their print density (how many characters they can encode per lineal inch), by how easy they are to print using low resolution printers, and by several other attributes. Modern bar code scanners can read all of these symbologies automatically,
and most bar code printing packages can print all of these symbologies
and many more.
The bar code has revolutionized the way business works. Bar coding is far more efficient and accurate than conducting manual data entry. Consider the following: The rate of mistakes in human data entry: The rate of mistakes in bar code data entry: No matter what your business is, automatic data collection using bar
code technology can help improve your operations while reducing costs,
increasing productivity, and enhancing profits.
Around the world, bar coding is employed almost everywhere data is anually
entered into a computer. Manufacturers, distributors, retailers, public
utilities, communications companies, government agencies, financial services,
health care providers, schools, government agencies, transportation companies,
and virtually every other type of industry are using bar code technology
to replace keyboard data entry.
Today, many different standards have been developed by a number of industries. While the standards can sometimes be confusing, they are necessary and very useful. Without them, different companies would be forced to develop their own bar code standards, and the resulting wide variety would create problems and confusion. KMART, WalMart, Sears, and other similar retailers have bar code label standards for suppliers. Auto industry bar code standards have been developed by the Automotive Industry Action Group (AIAG) and affect 28,000 suppliers. The U.S. Department of Defense insists suppliers use a standard bar code system or lose DOD business. Standards usually define a method of identifying an individual product
or a shipping container that will be scanned by an independent trading
partner. The standard defines a way to identify the product, the contents
of a shipping container, and sometimes other pertinent information about
the shipment such as lot number, purchase order number, and ship to address.
Using bar code standards does not mean abandoning your existing part numbering
system. To avoid the problems this would cause, companies develop a cross
reference of the old number to the new number in their computer. Alpha
Systems professionals can help you determine the appropriate standards
for your business and industry.
The primary usage of bar codes is for product identification, which is
required in warehousing, at retail check out, and in manufacturing. Any
application that allows automatic input of identifiers is a potentially
good fit for a bar code solution.
Scanning is the act of collecting information by use of a scanning device.
Data collection typically refers to a software function that assembles
the scanned information into a useable form.
Bar code scanners are generally categorized into the following types of devices:
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