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Bar Code Symbologies
The majority of all bar codes are printed on thermal transfer labels. These stickers
of black bars of various widths and lengths are a langue called symbologies. The
spaces and bars encode information about the product and when scanned, provide this
information automatically. The scanned information can then be entered without
errors, making bar codes a more accurate way of entering information. Because different industries have uniquely different needs, several types of bar
codes have been developed, each speaking different languages, are known as symbologies.
The following is a brief explanation of some of the more common symbologies. The most popular symbology used is Code 39 and is used for identification, inventory,
tracking and labeling. The characters for Code 39 encoding include uppercase letters
as well as numbers and Code 39 is self-checking. However, if there is additional
security required, there is an option of a check character. Bar codes used for encoding zip codes for the Postal Service, are Postnet bar.
In addition, with Postnet bar codes, instead of the bar's width varying, the bar
height of the Postnet alternates, with every number represented by 5 bars. Self-checking bar codes use a symbology that is designed to check itself, when it
has been read by a scanner ensuring that one character is not interpreted for another
character. When self-checking bar codes are scanned, the characters are added and
a calculation is made to confirm the number. This calculation is different for
the different types of bar codes and if the calculation is incorrect for that bar
code, then the bar code reading is rejected and the information is not transferred. The next type of bar codes is the Universal Product Code or UPC, which is the original
bar code. The first item ever purchased using the UPC was a pack of Wrigley's Juicy
Fruit chewing gum. These are mostly used in the grocery and retail industries.
EAN, JAN, and ISSN bar codes are expanded forms of the UPC. EAN bar codes are used
in Europe and JAN bar codes are used in Japan. ISSN bar codes are used on books
and magazines. It is a misconception that the price of the item is actually in the bar code. The
UPC code contains information that can be extracted from an inventory database when
the UPC is scanned. It is for this reason that when price changes occur, the UPC
label does not have to be replaced. The UPC uses only a numeric system with a check
character in the lower right hand corner. In addition to the check character, optional
2 or 5 digit numbers can be placed to the right of the main symbol, providing additional
encoding options. Code 128 bar codes are primarily used in the shipping industry, because it is a
very high-density linear symbology, which can encode text, numbers, several functions
as well as all 128 character ASCII character set, which are all members of the standard
code for representing characters by binary numbers. Interleaved 2 of 5 bar code symbology, is used by shipping and warehouse industries
as well as in the medical field. This code only varies in length and numeric and
is a continuous symbology, with each character consisting of 5 bars and 5 spaces.
This is also the highest density symbology for numeric data. The newest technology in bar codes is the 2D or two-dimensional bar codes, which
have the ability to store large amounts of data. Unlike one-dimensional or traditional
bar codes, 2D bar codes are a very high-density non-linear symbology. 2D bar codes
also have the ability to encode photos, images, fingerprints, and other such data. However, as wonderful as 2D bar codes sound they do have several disadvantages associated
with them, primarily that fact that the software is considerably more expensive
and you most have a special scanner in order to read the 2D bar code symbologies. There are several other scanned symbologies, which are used in addition to bar code
symbologies. Such as OCR or Optical Character Recognition, which are used independently
of the bar code. OCR-A are used to format the ISBN number for books, while the
OCR-B is used for UPC, EAN, JAN, and ISSN bar codes. Since their invention, bar codes have been improved upon making it easier for us
to maintain inventory as well as have the ability to track shipments. Who knows
how far bar codes will advance in the future.
Small business guides: , Thermal Transfer Labels Guide.com |
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