Barcode Symbologies Guide

SYMBOLOGY CONFIGURATIONS

Barcode symbologies can be loosely be subdivided into four different categories.

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Linear

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2-D Stacked

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2-D Matrix

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Composite

* Note: Symbologies shown are not represented at actual size!

LINEAR SYMBOLOGIES

A linear bar code symbology is a single row of bars or spaces. These are the most common forms in use today.

2-D STACKED SYMBOLOGIES

2-D Stacked Symbologies look like conventional linear barcodes stacked on top of each other. Multiple rows stacked on top of each other have the same length and touch each other.

2-D MATRIX SYMBOLOGIES

2-D Matrix Symbologies cannot be described as traditional barcodes. They encode data into a two-dimensional pattern of data cells. These are usually two different colours (black & white) and the cells maybe squares, dots or polygons.

UCC/EAN COMPOSITE SYMBOLOGIES

UCC/EAN Symbologies are based around the PDF417 symbology there are new standards under development for this emerging symbology. Note: Symbologies shown are not represented at actual size.

BARCODE SYMBOLOGIES AND APPLICATIONS

Code 39

Code 39 was the first bar code developed to encode alphabetic characters. The character set includes the 26 alphabetic characters, 10 numeric and 8 special characters.

Each Code 39 symbol has the following structure:

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Leading quiet zone.

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Start Character.

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Data.

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Check Digit (Optional).

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Stop Character.

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Final quiet zone.

It is known as Code 39 because each character has 9 elements; 5 bars and 4 spaces. Out of these nine elements, three of them are wide. It is a discrete symbology (i.e. there is a space between each character that is not part of the barcode). Code 39 is relatively easy to print. It is a ratio based symbology having only two widths of elements; wide:narrow. The ratio can range from 2.0:1 to 3.0:1

Code 39 applications

Code 39 is a very popular barcode symbology. Its capability to encode alphanumeric data has resulted in wide acceptance. Many organisations will use it for internal applications. It has a wide use in industrial applications, especially in the motor industry.

Interleaved 2 of 5

Interleaved 2 of 5 was developed to improve the low density of the original discrete 2 of 5 symbology. It is a high-density continuous code. Every barcode character actually encodes two digits; one in the bars and one in the spaces. This is a numeric-only barcode with data encoded in pairs of digits.

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Interleaved 2 of 5 has the following structure.

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Leading quiet zone

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Start pattern

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One or more pairs of data characters

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Stop character

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Final quiet zone

It is called Interleaved 2 of 5 because every character has 5 elements, 2 of which are wide. The interleaving is created by the fact that digits are encoded in pairs. Interleaved 2 of 5 is relatively easy to print. It is a ratio based symbol having only two widths of elements; wide:narrow. The ratio can range from 2.0:1 to 3.0:1

Interleaved 2 of 5 applications

A major application is its use in the EAN system. It is used to identify trade units by a bar code on the outer case carton of bulk packaging. Interleaved 2 of 5 is used here because of its ease of printing on corrugated cardboard. Even pressure when printing is assured by the use of bearer bars surrounding the symbol on all four sides. These bearer bars also ensure no misreads occur.

There have been many other traditional applications for this symbology due to its high-density data encoding. You should be aware that this is not the most secure bar code symbology. Unfortunately, a partial scan (i.e. one that does not include both quite zones) has a high probability of decoding as valid, but shorter Interleaved 2 of 5 symbols.

For example, 14-digit Interleaved 2 of 5 code could be misread as a valid 6 digit Interleaved 2 of 5 code. This is because the start and stop patterns can be duplicated within the symbol. Because of this, Interleaved 2 of 5 is best used in fixed length data applications. The reader can be programmed to accept only symbols of the correct length. Any others will be rejected.

UPC-A

The Uniform Product Code (UPC) has been successfully used in the retail industry in the United States and Canada since 1973. This is a coding system as well as a symbology. It is designed to uniquely identify a product and its manufacturer. The UPC-A code is a 12 digit numeric code. The first six digits represent the manufacturer, the next five digits are a unique product identifier and the twelfth is a check digit.

The first six digits are allocated by the UCC (Uniform Code Council). The actual data is encoded as two bars and two spaces within seven modules. The symbology allows omni-directional scanning i.e. presenting the code in any orientation to certain types of scanner.

UPC- A-Applications.

UPC-A is normally only used in the retail sector in the United States and Canada.

UPC-E

Is a fixed length, 6 digit numeric code. It is a compressed code ideal for use on small packages. It is also known as the zero suppression version of UPCA. It allows manufacturers to encode a limited number of 12 digit codes in six digits. The actual data is encoded as two bars and two spaces within seven modules. The symbology allows omnidirectional scanning i.e. presenting the code in any orientation to certain types of scanner.

UPC- E-Applications.

UPC-E is normally only used in the retail sector in the United States and Canada.

EAN 8 & 13

The EAN (European Article Numbering) system has two common versions. The EAN-13 and EAN-8 encoding 13 and 8 numeric digits respectively. The EAN symbology was developed for one requirement: to enable grocery products to be scanned at the Point of Sale. The symbol contains numeric data only.

The EAN (European Article Numbering) system has two common versions. The EAN-13 and EAN-8 encoding 13 and 8 numeric digits respectively. The EAN symbology was developed for one requirement: to enable grocery products to be scanned at the Point of Sale. The symbol contains numeric data only.

The symbology allows omni-directional scanning i.e. presenting the code in any orientation to certain types of scanner. The most commonly seen symbol in Europe is the EAN-13 symbol. The symbology must not be used without adhering to the rule of the numbering system. Manufacturers of products carrying the EAN symbol must register the company and product to a national coding authority. Each country will have a coding authority. The authorities are responsible for assigning a code to each manufacturer and maintaining a manufacturer/code database. In Europe, the International Article Numbering Association is responsible for this task.

On a 13 digit symbol, the first two or three digits are the country of origin, the next four or five represent the manufacturer’s code and the remaining digits generally provide the product code. The 13th digit is the check digit.

EAN 8 & 13 Applications.

EAN 8 & 13 is normally only used in the retail sector.

Code 128

The name Code 128 derives from the fact that you can encode 128 different data characters from the full ASCII set. This is a very high-density alphanumeric bar code symbology. It is variable length and continuous with 4 element widths. Each character has 11 modules, which may be either dark or light. Each character has 3 bars and 3 spaces. Each character begins with a bar and ends with a space.

Of all the linear symbologies Code 128 is the most flexible. It supports numeric and alphanumeric characters and when using character set ‘C’ has the highest number of characters per inch in a variable length code.

Each character can have one of three meanings, depending upon which of the character sets are used. Three different start characters tell the reader which character set is being used, and three shift codes allow the changing of the character sets within the symbol.

Set A includes numeric, upper case alpha and ASCII control character. Set B includes numeric and both upper and lower case alpha characters. Set C encodes pairs of numeric data into single bar code characters.

For example, the same character can be represented as:

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Set A CR

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Set B m

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Set C 77

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The code 128 has the following structure:

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Leading quiet zone

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Start character

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Data characters

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Stop character

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Modular 103 check digit

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Ending quiet zone

Code 128 Applications

Code 128 is being used in many applications due to its flexibility. Many formats of data can be encoded.

EAN-128

A subset of Code 128, using a special Code 128 character creates the EAN-128. The Function Code 1 (FNC 1), when encoded immediately after the start character has been reserved to indicate that the data follow conforms to the EAN/UPC structure. The ANA, EAN, and UCC have reserved its usage.

EAN-128 Applications

This is largely used in retail distribution to allow the tracking of serialized cartons.

Codabar

Codabar is a numeric only symbology. It has 4 different start and stop characters that can be used to identify different types of data. Using a correct combination of these start/stop characters it is possible to read two adjacent bar codes simultaneously.

Codabar Applications

Codabar was predominantly used in the blood transfusion industry because of its ability to ensure two bar codes are read simultaneously. Its use in this application is reducing with the acceptance of Code 128 as its successor.

Code 93

Code 93 was designed to be a high-density variant of Code 39. It can encode the full 128 ASCII characters. Code 93 is a multiple width symbology with two mandatory check digits.

Other linear barcode symbologies

There are many symbologies that you may come across. In most cases, those listed previously will be suitable for most applications. There are a number of others that are still in use.

Amongst these are:

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Telepen

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MSI Plessey

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Code 11

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Discrete 2 of 5

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Nixdorf code

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Post net

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State net code

PDF417

The most common 2-D stacked code today is the PDF417. This is a variable length symbol. Each character consists of 4 bars and 4 spaces in a 17-module length. This is a (17,4) structuregiving rise to the symbology name. There are 929 character values in each of three different sets. A given row uses one character set whilst the two adjacent rows use different sets. Because no row uses the same set as its neighbor the scanner is able to determine when it completes one row. The number of rows and the row length is variable allowing the size to be adjusted to suit the label. Each code consists of 3 to 90 stacked rows surrounded by a quiet zone on all four sides. The PDF417 can exceed over 1000 characters depending upon its content.

DataMatrix

Is a two-dimensional variable length symbology capable of encoding ASCII characters. Each code has a unique perimeter pattern that is used to determine the orientation. Two of the outside rows are solid, forming the letter ‘L’ and the opposite two sides use alternating black and white patterns which help synchronize the decoding process. Up to 2334 characters can be encoded.

QR Code

QR code (abbreviated from Quick Response Code) is the trademark for a type of matrix barcode (or two-dimensional barcode) first designed for the automotive industry in Japan. Initially patented, its patent holder has chosen not to exercise those rights. Recently, the QR Code system has become popular outside the automotive industry due to its fast readability and greater storage capacity compared to standard UPC barcodes. The code consists of black modules (square dots) arranged in a square pattern on a white background. The information encoded may be made up of four standardized types (“modes”) of data (numeric, alphanumeric, byte / binary, Kanji), or through supported extensions, virtually any type of data.

Maxicode

Developed by United Parcel Service for the automatic sortation and tracking of packages. It is a fixed length alphanumeric symbology composed of an array of interlocking hexagons surrounding a circle pattern. 144 characters can be encoded.

UCC/EAN Composite

The UCC/EAN composite symbology is likely to be adopted as a standard for drug identification. It has been designed to offer increased security, safety and control in drug distribution and dispensing. It may also be adopted by other industries including healthcare, electronics, and telecommunications. With 3 different subsets, the code can contain up to 2361 digits including authorisation number, expiry date, and batch number. A scanner that is ideally suited to scanning this symbology is the M2000 Cyclone from Symbol Technologies.