Codabar
Encyclopedia
Codabar is a linear barcode
symbology
developed in 1972 by Pitney Bowes
Corp. (http://other.lookstrike.com/barcode/demo/html/codabar.php). It is also known as Codeabar, Ames Code, NW-7, Monarch, Code 2 of 7, Rationalized Codabar, ANSI/AIM BC3-1995 or USD-4.
Although Codabar has not been registered for US federal trademark status, its hyphenated variant Code-a-bar is a registered trademark.
It was designed to be accurately read even when printed on dot-matrix printers for multi-part forms such as FedEx
airbills and blood bank
forms, where variants are still in use as of 2007. Although newer symbologies hold more information in a smaller space, Codabar has a large installed base in libraries. It is even possible to print Codabar codes using typewriter-like impact printers, which allows the creation of a large number of codes with subsequent numbers without having to use any digital equipment. After each printed code, the printer's stamp is mechanically turned to the next number, as for example in mechanical mile counters.
.
The variants of Codabar in commercial and public use will sometimes define a proprietary check digit.
For instance in an all-numeric string, the check digit algorithm might double the odd digits, take modulo
9, sum the results with the even digits, and represent the total in modulo 10.
The alphabet characters A, B, C, D, and in some specifications, E, N, asterisk, and T are used in matching pairs to mark the beginning and end of the barcode. They do not appear in the body of a Codabar string.
Each character comprises 7 binary identifiers (4 bars and 3 spaces). Each identifier or element is made up of a certain multiple of constant-width modules. Different specifications allow for different width modules, the smallest being 0.0065 inches, allowing 11 characters per inch to be encoded. Logical 0s and 1s are represented by narrow and wide elements respectively.
Barcode
A barcode is an optical machine-readable representation of data, which shows data about the object to which it attaches. Originally barcodes represented data by varying the widths and spacings of parallel lines, and may be referred to as linear or 1 dimensional . Later they evolved into rectangles,...
symbology
Barcode
A barcode is an optical machine-readable representation of data, which shows data about the object to which it attaches. Originally barcodes represented data by varying the widths and spacings of parallel lines, and may be referred to as linear or 1 dimensional . Later they evolved into rectangles,...
developed in 1972 by Pitney Bowes
Pitney Bowes
Pitney Bowes Inc. is a Stamford, Connecticut-based manufacturer of software and hardware and a provider of services related to documents, packaging, mailing, and shipping, collectively referred to as mailstream. The company has approximately 36,000 employees worldwide. It is one of 87 existing...
Corp. (http://other.lookstrike.com/barcode/demo/html/codabar.php). It is also known as Codeabar, Ames Code, NW-7, Monarch, Code 2 of 7, Rationalized Codabar, ANSI/AIM BC3-1995 or USD-4.
It was designed to be accurately read even when printed on dot-matrix printers for multi-part forms such as FedEx
FedEx
FedEx Corporation , originally known as FDX Corporation, is a logistics services company, based in the United States with headquarters in Memphis, Tennessee...
airbills and blood bank
Blood bank
A blood bank is a cache or bank of blood or blood components, gathered as a result of blood donation, stored and preserved for later use in blood transfusion. The term "blood bank" typically refers to a division of a hospital laboratory where the storage of blood product occurs and where proper...
forms, where variants are still in use as of 2007. Although newer symbologies hold more information in a smaller space, Codabar has a large installed base in libraries. It is even possible to print Codabar codes using typewriter-like impact printers, which allows the creation of a large number of codes with subsequent numbers without having to use any digital equipment. After each printed code, the printer's stamp is mechanically turned to the next number, as for example in mechanical mile counters.
Check digit
Because Codabar is self-checking, most standards do not define a check digitCheck digit
A check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary checksum. It consists of a single digit computed from the other digits in the message....
.
The variants of Codabar in commercial and public use will sometimes define a proprietary check digit.
For instance in an all-numeric string, the check digit algorithm might double the odd digits, take modulo
Modulo operation
In computing, the modulo operation finds the remainder of division of one number by another.Given two positive numbers, and , a modulo n can be thought of as the remainder, on division of a by n...
9, sum the results with the even digits, and represent the total in modulo 10.
Encoding
Depending on the particular specification, for example the Association for Automatic Identification and Mobility's Uniform Symbol Specification, the body of a Codabar string may only encode the numerals 0 through 9. Some variants allow the symbols dollar, dash, plus sign, colon, slash, and dot.The alphabet characters A, B, C, D, and in some specifications, E, N, asterisk, and T are used in matching pairs to mark the beginning and end of the barcode. They do not appear in the body of a Codabar string.
Each character comprises 7 binary identifiers (4 bars and 3 spaces). Each identifier or element is made up of a certain multiple of constant-width modules. Different specifications allow for different width modules, the smallest being 0.0065 inches, allowing 11 characters per inch to be encoded. Logical 0s and 1s are represented by narrow and wide elements respectively.
| Char. | Pattern | Bars | Spaces |
|---|---|---|---|
| 0 | lll l | 0001 | 001 |
| 1 | lll l | 0010 | 001 |
| 2 | ll ll | 0001 | 010 |
| 3 | l lll | 1000 | 100 |
| 4 | lll l | 0100 | 001 |
| 5 | lll l | 1000 | 001 |
| 6 | l lll | 0001 | 100 |
| 7 | l lll | 0010 | 100 |
| 8 | l lll | 0100 | 100 |
| 9 | ll ll | 1000 | 010 |
| - | ll ll | 0010 | 010 |
| $ | ll ll | 0100 | 010 |
| : | llll | 1011 | 000 |
| / | llll | 1101 | 000 |
| . | llll | 1110 | 000 |
| + | llll | 0111 | 000 |
| A or T | ll l l | 0100 | 011 |
| B or N | l l ll | 0001 | 110 |
| C or * | ll l l | 0001 | 011 |
| D or E | ll l l | 0010 | 011 |
External links
- EAN MediaWiki extension, a MediaWiki extension, visualizing Codabar/Code39/EAN-13/EAN-8/UPC-A barcodes by specifying only the numbers/symbols in the wiki-text.
- Free Online Codabar generator.