| Technologies: Bar Code / Frequently Asked Questions |
Bar Code Frequently Asked Questions (FAQ)Do you have a question that is not listed below? Email us, and we'll research a response. 1. What is a bar code? Q. What is a bar code? Most linear bar codes are nothing more than "license plates" that identify an item. The numbers and/or letters stored in the bar code are unique identifiers that, when read, can be used by a computer to look up additional information about the item. The price and description of the item is generally not stored in the bar code. The data is read from the bar code, sent to a computer, and the computer looks up the price and description of the item from the computer's database. Bar codes are read by either scanning a point of light across the symbol or capturing a video image of the symbol and measuring the lengths of white spaces and black bars. The lengths and positions of the spaces and bars are analyzed by a computer program and the data is extracted. The relative widths of both the bars and spaces code the data stored in the bar code. The bar code reader detects these relative widths and decodes the data from the bar code. Bar codes can be printed using most computer printers. The simplest way to print a bar code with your computer printer is to use a bar code font. You install the font on your computer just like any other font, and you can switch to the bar code font the same way you switch to any standard font. A company can also order labels preprinted with bar code from vendors that specialize in printing bar codes. Q. Are there different bar codes? There are three basic types of bar codes: linear, 2D, and composite. Linear bar code symbols are easily identified by their tall printed bars of varying widths. There are many linear symbols but the ones used most frequently are called UPC-A, UPC-E, EAN-8, EAN-13, Code 39, Code 128, and ITF (Interleaved 2-of-5). Two-dimensional (2D) bar code symbols are broken into two major groups called Matrix symbologies and Stacked bar codes. Matrix symbologies look like a matrix of printed dots and stacked bar codes look like linear bar codes with very short bars stacked on top of each other. Composite symbols are a category of bar codes that combine an interdependent linear and 2D symbol. See AIM's book called Understanding 2D Symbologies for a summary of the most common 2D and composite symbols. Q. Which bar code do I use? If you need a copy of a bar code specification that tells you what the bars and spaces mean and what they are capable of encoding, AIM sponsors the development and publishing of bar code specifications . A notable exception to this rule would be the symbol specification for U.P.C. symbols, which is available from GS1 (formerly, UCC). If you need to comply with a customer's bar code application, then you must obtain a copy of the application specification and whatever bar code is required by the specification is what you need to use. Industry standards tell you what bar code to use, how to build the information inside it, what size to print the bar code, where to put the bar code on your package or container, and what the minimum quality level is for your bar code. Q. How do I get a bar code number for my product? In the USA, a company can obtain a unique six digit company identification number by becoming a member of GS1-US (formerly the Uniform Code Council (UCC)). In the rest of the world, contact GS1 (formerly EAN International (EAN)). You must apply for membership and you will be assigned a unique company identification number for use on all your products. Note: Take a look at the UPC/EAN page which explains how to apply for a UPC/EAN number and gives technical formation about UPC/EAN. What you get is a unique company identification number which is a 6 or 7-digit number. This is the first part of the product UPC/EAN code. The remaining 6 digits are assigned by you (not GS1) for a specific product. Each number must be unique for a particular product and product size. If you have an 8 oz. size and a 12 oz. size, for example, you need to assign two unique numbers. If you want to bar code a book, you use the International Standard Book Number (ISBN). Here is a link to a website that describes the process. If you are bar coding a monthly publication, you use the the International Standard Serial Number (ISSN). Here is a link to a website that describes the process for magazines. Q. What size do I make a bar code? If you are trying to comply with an industry specification, an application specification will define the size that is needed in order to be in compliance. Most application specifications are based on a particular scanning environment and call for a specific bar code symbology, size of the narrow element, and height of the code. Q. How do I print a bar code? Keep in mind that whatever technology you use, it is your responsibility as the printer of these bar codes to verify that they conform with industry specifications and will be readable with any scanner that can decode the symbology you have printed. You can only do this with a bar code verifier. More about bar code verification. Q. How do I know the bar code that I printed is good? For more background on bar code print quality, you may download (PDF format) the AIM Layman's Guide to ANSI Print Quality Guideline. Q. Can inkjet be used for bar code applications? AIM would like to thank Trident - An ITW Company for providing the answer to the above question. |