News about Barcode Scanners
[22/05/2010] Barcode symbology
Barcode symbology is the method that each barcode type uses to store date; not all barcodes use the same symbology and not all barcode scanners can read every barcode label. However, some of the barcode symbologies used today have become standard in different industries.
The most common factors that distinguish one barcode symbology from another are the:
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Character set used by the barcodes; the character sets are of three types: digits only, digits and letters, or digits, letters and control characters.
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Density of the barcodes is represented by the amount of characters that are found in one inch of barcode. The density itself is determined by the symbology used, by the wide to narrow elements ratio, and by the barcode’s x-dimension (the width of the narrowest barcode bar). The x-dimension of a barcode is measured in mils (one thousandth of an inch) and even though 7 mils is the most commonly found x-dimension, barcodes with 3mils are widely used as well.
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1D (one dimensional) barcodes are the ones that most people are familiar with – these are linear barcodes that are represented by vertical black bars and white spaces between them. The 1D barcodes usually have space on the left and on the right of the barcode, which space servers as starting and ending point to the scanner; most barcodes have “module check” section as well, which helps confirming that the barcode has been read accurately.
- 2D (two dimensional) barcodes store data in a two-dimensional array and the barcode label has to be read in its entirety. 2D barcodes can store as many as 7000 characters and can be either black and white or in color.
Common barcode symbologies
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UPC symbology. The barcodes that use this technology are the ones found in the retail stores; the data stored by these barcodes is the item number and the manufacturer ID number. The UPC barcode labels are always the same width and they have to comply with the standards, imposed by the Universal Products Commission.
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The CODE 39 symbology is used in many industries and is the second most widely used symbology; In 1981 CODE 39 was adopted by the US Defense Department for all products. The CODE 39 barcodes can store numbers, letters and some special characters as well.
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The CODE 128 symbology is similar to the CODE 30 one, but it is of higher density and permits the usage of more characters. A version of the CODE 128 symbology, called GS1-128, is used in the packing and shipping industries.
- Interleaved 2 of 5 symbology is a two-width symbology, which stores digits only. The name comes from the fact that two out of the five bars are wide and the symbology is used in wholesale, libraries, and others.
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The Postnet barcode symbology is used by the US Postal Services and was specifically developed in order to allow the zip codes to be encoded as half-length or full-length bars.
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The PDF417 symbology is a 2D (two-dimensional) symbology, which was developed by Symbol Technologies, but is now a public domain. As the name indicates, this high-density barcode symbology stores PDF (portable data files) instead of just a reference number. PDF417 is used on ID documents, in the transport industry and for inventory management.
- The DataMatrix symbology is a true 2D symbology, which uses modules that are arranged in either rectangular or square patterns. Raw data or text can be directly stored and the existence of error correction codes permits the barcode labels to be read even if they are partially damaged.
Other articles from this category:
[27/04/2010] What is Barcode Scanner?
[27/04/2010] What are the scanning methods available?
[22/05/2010] Barcode reader - general explanation
[22/05/2010] What are the scanning methods?
[22/05/2010] Types of technology in barcode scanners.
[22/05/2010] Housing types
[22/05/2010] Methods of connection
[22/05/2010] Resolution of barcode labels
[22/05/2010] Hand-held versus fixed scanners
[22/05/2010] Manhattan Barcode Scanner Quick Setup Guide
[22/05/2010] Corded Barcode Scanners
[22/05/2010] What are barcodes used for?
[09/07/2010] Why Track Inventory
[11/01/2011] Cordless Scanner Benefits
[11/01/2011] Wireless Barcode Scanners
[11/01/2011] CCD Barcode Scanners
[11/01/2011] Symbol Barcode Scanners
[11/01/2011] Barcode scanners not only useful in supermarkets
[11/01/2011] Barcode Advancements
[11/01/2011] Barcode Scanners and Barcode Printers
