Barcode Technology : Linear Barcodes

Linear Barcode Standards

Linear barcodes use single row of black and white bars. Examples of linear barcodes are:

· ISO/IEC 15420 Bar code symbology specification – EAN/UPC

UPC (Universal Product Code) uses 12-digit numeric containing a unique manufacturer ID number, and product number. EAN (European Article Numbering) is similar to UPC except the fact that it uses 13-digit numeric.

· ISO/IEC 16388 Bar code symbology specifications – Code 39

It is a discrete barcode. It implies that a single character is represented by a fixed pattern of bars. Each character is made up of 9 (5 black & 4 white) bars. Code 39 barcode symbology supports 43 characters set plus an additional character used as a delimiter or start/stop character. The start/stop character always occurs as the first and last character in a complete barcode and is represented in the human readable text by the * character.

The 43 character set includes the following: 1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ - . $ / + % SPACE.

A check digit is generally not used with Code 39. The check digit is the modulus 43 sum of all the character values in the message and it is printed as the last data character.

· ISO/IEC 15417 Bar code symbology specification – Code 128

CODE 128 allows the full ASCII 128 character set to be encoded. Each bar or space can be one of four different unit widths. The narrowest possible bar or space will thus be one quarter the width of the widest. It permits bidirectional scanning and theoretically, there is no restriction on the number of characters allowed in each symbol.

Code 128 has three different character sets as Code Set A, Code Set B and Code Set C. Any of these codes may be selected by appropriate selection of start character. The Code 128 Specification requires the inclusion of a check digit. The check digit is a Modulus 103 checksum.

Each character in the barcode symbol is composed of three bars and three spaces. The stop character has four bars and three spaces.

· ISO/IEC 16390 Bar code symbology specifications – Interleaved 2-of-5 (ITF25)

Primarily used in the warehouse industry, Interleaved 2 of 5 encodes any even number of numeric characters in the width of both bars and spaces. It is called “Interleaved” because 2 characters are encoded in a unit of 5 bars and spaces. It uses both bar and space width to encode information so the density of ITF25 is much higher. Interleaved 2 of 5 is a numeric symbology and it character set only include 10 digital characters.