Defining Code 128 Barcode

Published: 05th March 2010
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Code 128 (introduced in 1981) is a very high-density alpha-numeric symbology. Code 128 is a variable-length code and encodes the full 128 ASCII character set. It has two forms of error checking, making it a very stable barcode. It is more compact and flexible than Full ASCII Code 39 and Interleaved 2-of-5.





Applications

The most common use of Code 128 is for shipping labels. Code 128 is also used on ID cards.



Benefits

Code 128 is one of the most efficient general-purpose barcode. It can handle any data and encodes the barcode in a relatively lot smaller space by using various compression techniques.



Limitations

Being a high density barcode, Code 128 cannot be read easily using low resolution scanners.



Technical Specifications

Code 128 barcode is an alpha-numeric, variable-length, high-density code . Code 128 has 106 different bar and space patterns and each pattern can have one of the three different meanings, depending on which of the three different character sets is employed. Special start characters tell the reader which of the character sets is initially being used and three special shift codes permit changing character sets inside a symbol. Start Code A allows encoding standard alpha-numeric keyboard characters plus control characters and special characters. Start Code B includes all standard alpha-numeric keyboard characters plus lower case alpha and special characters. Start Code C includes a set of 100 digit pairs from 00 to 99 and can be used to double the density of encoding numeric-only data. Code 128 also employs a check digit for data security.



Code 128 data can be of any length. A Code 128 barcode consists of a leading quiet zone, one of the three start codes, the data itself, a check character, a stop character, and a trailing quiet zone.



Additional Information

If you need to generate a numeric only barcode with an even number of characters try using Code 128 C, it will produce a very dense barcode for you. Start Code C includes a set of 100 digit pairs from 00 to 99 and can be used to double the density of encoding numeric-only data.



Code 128 also allows encoding of four special function codes (FNC1 - FNC4). The FNC codes define instructions for the barcode reader. The meaning of function code FNC1 and FNC4 were originally left open for application specific purposes. Recently an agreement was made between Automatic Identification Manufacturers Association. (AIM) and European Article Numbering Association(EAN) to reserve FNC1 for use in EAN applications. FNC4 remains available for use in closed system applications. FNC2 is used to instruct a barcode reader to concatenate the message in a barcode symbol with the message in the next symbol. FNC3 is used to instruct a barcode reader to perform a reset. When FNC3 is encoded anywhere in a symbol, any data contained in the symbol is also discarded.



We here at Jolly Technologies hope this information is helpful. Please feel free to come visit our website http://www.jollytech.com to download a free 30 day trial of our two barcode software solutions; Label Flow, a design and production software for barcodes, and Asset Track, a asset tracking software utilizing barcodes. The free trial is a full version of our software and if you call us up at 1-888-255-6559 to set up a


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