Bar codeA bar code is a series of vertical bars of various widths that are used to represent (usually) twelve or thirteen digits by a varied pattern of bars. A laser scanner (reader), which identifies the correspondence between the bars and the digits, usually reads the bars. The information is then sent to a computer where it is processed. Almost everyone is familiar with the striped bars found on grocery and retail store items. These are bar codes, or more specifically, the North American Show Universal Product Code (UPC) first appeared in stores in 1973 (after having been created in 1971). Since then, they have revolutionized the sales industry. The UPC code consists of (usually) twelve pairs of thick and thin vertical bars that represent the manufacturer’s identity, product size and name. Price information, which is not part of the bar code, is determined by the store. Bar codes are read by handheld wand readers or fixed scanners linked to point of sale (POS) terminals. Beginning in 2005, the GS1 US (formerly the UPC) also began using another system. It is called the European Article Number (EAN) code. This internationally accepted system uses 13 numbers, instead of the original 12 numbers. The dark bars are one to three units wide and the light bars are from one to four units wide. In this way, each item is assigned a unique numeric code, which is printed as a bar code on packaging and materials. In addition, the Japanese Article Number (JAN) code has also been adopted. Bar codes are also used for non-retail purposes. One of the earliest uses for bar codes was as an identifier on railroad cars. Organizers of sporting events also take advantage of bar code technology. For example, as runners of the Boston Marathon complete the 26 mi (42 km) course in Massachusetts, they turn over a bar code tag that allows race officials to quickly tabulate results. From 1965 through 1982, the United States Post Office experimented with optical character recognition (OCR) and bar code technology to speed up mail delivery. In 2006, the Post Office utilized another type of bar code called the POSTNET bar code. Consisting of full and half height bars representing the zip-code and delivery address, the bar code allows mail to be sorted automatically at speeds of up to 700 pieces per minute. Bar codes used on retail books use the International Standard Book Number (ISBN) system, which identifies books on the basis of the books’ country of origin and its price. Originally, one-dimensional bar codes used only the bar’s width to encode. Two-dimensional bar codes are now also used to encode both horizontally and vertically. This two-dimensional system allows much more information to be encoded. Instead of lasers, they typically use digital cameras. Different types of two-dimensional systems include PDF417 (the most common two-dimensional code), MaxiCode (used by United Parcel Service [UPS]), and QR Code (primarily for Toyota parts and Japanese cell phones).
The following explains the format of a barcode.  A Barcode lengthB C Barcode symbolD Barcode heightE Start characterF Data (message)G Check digitH Stop characterThe right and left ends of the barcode symbol. Character to indicate start or end of the data. Bar patterns representing the data (numerical characters, alphabet, etc.) are arranged from left. A numeric value calculated to check for read error. It is appended directly after the barcode data. Barcode length defines the total length including the right and left quiet zones. It is recommended to make the barcode as high as the printer permits. The following explains bars and spaces that are the minimum unit to form a barcode. A barcode is a combination of narrow and wide bars and spaces. Each bar and space are named as listed below:
Narrow and wide widths are determined at the following ratio: The width of a narrow bar is a key for selecting a barcode reader. Barcodes in the categories of CODE 39, CODABAR and ITF consist of bars and spaces that have two steps of narrow and wide widths. It is named the "binary level" barcode. A B Wide barC Wide spaceD Narrow spaceBarcodes in the categories of EAN and CODE 128 consist of bars and spaces that have four steps of narrow and wide widths. It is named
the “multiple level” barcode. A check digit is a numeric value calculated to check for read error.
INDEX What does a barcode represent?A barcode, consisting of bars and spaces, is a machine-readable representation of numerals and characters. Today, stripes as shown below on packages of products sold at supermarkets, convenience stores and other stores are ubiquitous. These are barcodes.
Which of the following data can be represented by using barcodes?The combination of black and white bars (elements) represents different text characters which follows a set algorithm for that particular barcode. Barcode contains information about a product like; price & weight of the product, date of manufacturing and expiry, name of the manufacturer etc.
What is the structure of a barcode?Barcode Structure
Barcode is a series of varying width vertical lines (called bars) and spaces. Bars and spaces together are named "elements". There are different combinations of the bars and spaces which represent different characters.
How many lines does a bar code have?Discrete barcodes
In this barcode, each digit is encoded using: three narrow lines, a single wide line, two narrow gaps, and a single wide gap. For each digit, these lines and gaps are placed in a different order.
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A barcode is a/an code that represents data with bars of varying widths or heights
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