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A UPC barcode. The Universal Product Code (UPC or UPC code) is a barcode symbology that is used worldwide for tracking trade items in stores.. The chosen symbology has bars (or spaces) of exactly 1, 2, 3, or 4 units wide each; each decimal digit to be encoded consists of two bars and two spaces chosen to have a total width of 7 units, in both an "even" and an "odd" parity form, which enables ...
A barcode or bar code is a method of representing data in a visual, machine-readable form. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines.
The barcode scheme does not contain a check digit (in contrast to—for instance—Code 128), but it can be considered self-checking on the grounds that a single erroneously interpreted bar cannot generate another valid character. Possibly the most serious drawback of Code 39 is its low data density: It requires more space to encode data in ...
In 1974, the Uniform Code Council (UCC) was founded to administer the standard. [1] On 26 June 1974, a pack of Wrigley's chewing gum became the first ever product with a barcode to be scanned in a shop. [1] [3] In 1976, the original 12-digit code was expanded to 13 digits, which allowed the identification system to be used outside the U.S.
These barcodes only represent the digits 0–9, unlike some other barcode symbologies which can represent additional characters. The most commonly used EAN standard is the thirteen-digit EAN-13, a superset of the original 12-digit Universal Product Code (UPC-A) standard developed in 1970 by George J. Laurer. [1]
Because Codabar is self-checking, most standards do not define a check digit. [3] Some standards that use Codabar will define a check digit, but the algorithm is not universal. For purely numerical data, such as the library barcode pictured above, the Luhn algorithm is popular. [4] When all 16 symbols are possible, a simple modulo-16 checksum ...
For instance, encoding the ASCII character "0" can be viewed as 10011101100, where a sequence of 1's is a bar and a sequence of 0's is a space. A single 1 would be the thinnest line in the bar code. Three 1's in sequence (111) indicates a bar three times as thick as a single 1 bar.
The POSTNET 11-digit barcode was the predominant postal addressing barcode in use until the Intelligent Mail barcode (also known in its early usage as OneCode Solution) [3] was introduced and implemented. The POSTNET barcode was replaced by the Intelligent Mail barcode in the fall of 2009, combining all previous Postal Service barcodes and ...