Wireless Barcode Scanners - A Primer on the Eight Most Used Symbologies

Wireless Barcode Scanners

In today's global economy, barcode technologies are changing rapidly. Symbologies that were common place 10 years ago are not being employed in new applications. Through all this change, there are still four basic criteria that define and characterize a specific symbology or code.

• Character set - alphanumeric or numeric
• Number of ASCII Characters - ranges from as few as 10 to the full complement of 128
• Maximum characters per inch - ranges from 9.4 at the lowest to 17.8 at the largest
• Variable length - This is a yes or no criteria, either a symbology is variable length or it is not

Off the 400 plus barcode symbologies in use globally today, eight are the most common. Following is a short description of each of those eight symbologies including their predominant uses:

1. Code 39 - It is variable length and known to be the most commonly used symbology in industrial barcode systems today. It has a alphanumeric character set with 43 ASCII characters. It gets its name from the configuration of the bars, three of the nine are wide and six bars are narrow. There are four special characters that when paired with the alphanumeric characters extend the code 39 to the full ASCII character set of 128. It is known for its ease of use and capacity for standard check digits for data security.
2. Code 128 - Uses the full 128 ASCII character set and is variable length. Each character is represented by 11 modules that can be one of four bar widths. It is the most easily read code with the highest message integrity due to a large number of separate check routines. Of the eight common symbologies, it is the most flexible. Due to its flexibility it is becoming the symbology of choice for new applications.
3. UPC-A (Universal Product Code - A) - Is fixed length and is most common in retail. It is the barcode used in grocery stores and other retail applications across the US. It is a 12 digit numeric only code. The first six digits are assigned to an entity by the Uniform Code Council, the next five are assigned by the entity and the last digit is used as check digit. A variation called UPC-E is a compressed six digit code used for small packages including magazines and books.
4. EAN/JAN - 13 - This is a fixed length code similar to the UPC-A code but encodes a 13th digit. The 12th and 13th digits generally are used to represent the first two digits of the 2 or 3 digit country code. A variation called EAN/JAN-8 includes four digits for the country code. These symbologies are most often used in international shipping and transportation applications.
5. Interleaved 2 of 5 - Is a variable length, numeric barcode typically used in industrial and master carton labeling. It uses bars to represent the first character and interleaved white spaces represent the second character. Each character has two wide elements and three narrow elements.
6. Code 93 - This code is similar to Code 39 but encodes more characters per inch. It encodes the full 128 ASCII character set and uses 9 modules arranged into 3 bars with adjacent spaces. Code 92 is used for some of the same applications as Code 39, but when more needs to be represented in the code.
7. Codabar - This is a variable length symbology capable of encoding 16 characters within any length message. Codabar is constrained in its use and its reliability and not recommended for new applications.
8. MSI Plessey - Is a variable length numeric symbology generally used in marking retail shelves. Each character consists of four bars with intervening spaces for each encoded digit, up to two symbol check digits and a reverse start code.

The above is intended as an introductory description of the eight most used barcode symbologies, not a basis for making business decisions on new applications. Solicit the advice of a professional that can make recommendations based on your specific business requirements.

This is the second in a series of articles intended to describe and inform on barcode technologies. The first step in any business decision is to have a basic understanding of the technology so that the available options are assessed objectively.
Wireless Barcode Scanner