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Bar Coding for Beginners

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A History of Barcodes
Bar code technology was first utilized commercially in 1966 when The National Association of Food Chains (NAFC), looking for a faster method of checking-out customers, called upon equipment manufacturers to get the job done. Common linear bar codes began to appear on grocery shelves in the early 1970’s, around the same time the Universal Grocery Products Identification Code or UGPIC was written as a set of industry standards by a company called Logicon Inc. By 1973, the Committee on Uniform Grocery Product Code suggested the UPC bar code symbology be used across the entire USA.

In 1974, one of the first UPC bar code scanners, manufactured by National Cash Register Co., was installed at a supermarket in Toy, Ohio called Marsh’s. During that same time, the first bar code-attached product was scanned at Marsh’s supermarket, a pack of chewing gum, which is to this day on display at the Smithsonian Institute’s National Museum of American History.

The first real attempt to utilize bar code technology in an industrial application setting was brought about by the Association of American Railroad in 1967. Seven years later, almost the entire fleet of railroad cars was labeled with bar codes. Unfortunately, the system was inadequate for a variety of reasons, and the whole concept was scrapped some years later. The bar code industry got a real jolt in 1981 when the US Department of Defense began using the Code 39 bar code, also known as LOGMARS, to mark all products purchased by the US military.

The bar code and auto-identification industry is alive and well and in virtually every market that exists today. From labeling thousands upon thousands of products for sale in the retail arena to bar coding your DVD collection for quick-and-easy access, the industry has taken over to become one of the core resources for logistics, document tracking and record keeping.
Bar Code Symbologies and Standards
Deciding which bar code to use can depend on a number of different factors, such as:
  • Industry standards and mandates
  • Intended purpose and use
  • Data to be encoded
  • Methods of printing and/or decoding

Each type of bar code symbology is a standard that defines the printed bar code symbol itself, as well as how a bar code scanner reads and decodes that printed bar code symbol. Industry standards are generally established when multiple entities (corporate or otherwise) are involved in the ID process. Bar code standards seek to define how to use the bar code symbology in a given situation. If an industry standard has been established for a specific implementation, that standard should always be used. If a standard does not exist for a specific implementation, there are a number of bar code symbologies to choose from depending on the requirements.

If the process of choosing the right bar code for your intended use is confusing, please refer to the following table that outlines the many standards, uses and symbologies today:

Established Bar Code Standard Intended Use or Purpose Required Bar Code Symbology
ABC Codabar Blood Bank Tracking Codabar
AIAG Automotive Item Identification DataMatrix
DOD UI US Dept of Defense Unique Identifier DataMatrix
EAN-8 & EAN-13 Retail Items (Worldwide) UPC/EAN
EAN-14 Shipping Cartons Interleaved 2of5 or Code 128
GTIN Global Trade Identification Code 128
GTIN-12 Global Trade Identification UPC
GTIN-13 Global Trade Identification EAN
GTIN-14 Global Trade Identification GS1-DataBar
ISBN, ISSN & Bookland Books & Periodicals EAN-13 with UPC/EAN
LOGMARS US Department of Defense Code 39
MIL-STD-130L US Department of Defense DataMatrix
SCC-14 Shipping Cartons Interleaved 2of5 or Code 128
SISAC, SICI Code Serial Numbers for Serial Publications Code 128
ISBT-128 Blood, Tissue & Organ Products Code 128
SSCC-18 Shipping Cartons Code 128
USPS Special Services US Mail Special Services Interleaved 2 of 5 or Code 128
UCC12, UPC-A & UPC-E Retail Items (USA & Canada) UPC
USPS Intelligent Mail USPS Mail Routing & Tracking 4 State
Bar Code Accuracy
Studies have indicated that a well-trained data entry operator generally makes a data-entry related error once every 300 keystrokes. Integrating bar code technology into the workplace can drastically increase production while reducing data entry errors. The bar code accuracy/misread issue was evaluated in a recent study at Ohio University Center for Automatic Identification. Following are some of the results:
Bar Code Symbology Worst-Case Accuracy Best-Case Accuracy
DataMatrix 1 Error per 10.5 Million Keystrokes 1 Error per 612.9 Million Keystrokes
PDF417 1 Error per 10.5 Million Keystrokes 1 Error per 612.4 Million Keystrokes
Code 128 1 Error per 2.8 Million Keystrokes 1 Error per 37 Million Keystrokes
Code 39 1 Error per 1.7 Million Keystrokes 1 Error per 4.5 Million Keystrokes
UPC 1 Error per 394,000 Keystrokes 1 Error per 800,000 Keystrokes
Common Bar Code Dimensions
Bar code specifications are provided depending on how the bar code will be implemented. In some cases, the bar code sizing parameters are given in inches but should be calculated instead in centimeters. To convert inches to centimeters, simply multiply the value in inches by 2.54. To convert millimeters to centimeters, multiply the millimeters (1 mil = .001 inches) value by .00254. For common barcode dimensions, please review the chart below:
Inches Centimeters Millimeters
.004 .01016 4
.006 .01524 6
.008 .02032 8
.010 .0254 10
.012 .03048 12
.014 .03556 14
.02 .0508 20
.04 .1016 40
.75 1.905 750
1.25 3.175 1250
Suggestions for Using Bar Code Fonts
  • Codabar Bar Code Fonts are the best choice when encoding approximately 30 number-only digits, as it is the densest, easy-to-use symbology, and it is self-checking.

  • Code 39 Bar Code Fonts are the best choice when encoding alpha-numeric characters such as uppercase letters, numbers, and the symbols (- . $ / + %) at approximately 20 digits. This symbology is easy to use and is self-checking.

  • Code 128 Bar Code Fonts or Universal Bar Code Fonts are best when encoding both uppercase and lowercase letters, numbers, punctuation and ASCII functions such as returns and tabs to approximately 40 digits.

  • Two Dimensional Bar Code Symbologies such as Aztec, QR Code, DataMatrix or PDF417 are the best choice when encoding any type of data over 40 characters.


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