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Barcode Definitions

ABC Symbol

The American Blood Commission (ABC) developed this symbol as a bar code standard for automated systems in the blood service community. The particular symbology used for the ABC symbol is Codabar.

AIM International (AIMI)

It is a global affiliation of trade associations whose member companies are involved with application of automatic identification technology. For more information access


The American National Standards Institute has served in its capacity as administrator and coordinator of the United States private sector voluntary standardization system for 78 years. Founded in 1918 by five engineering societies and three government agencies, the Institute remains a private, nonprofit membership organization supported by a diverse constituency of private and public sector organizations. For more information access

Aperture Size

The dimension of the opening through which the scanning beam passes. Normally used in conjunction with a wand (pen) type bar code scanning device. The aperture size will determine the bar code density which may be read with the scanning device.


The character set and code described in American National Standard Code for Information Interchange between data processing systems, communication systems and associated equipment. The ASCII set consists of both control and printing characters.

Aspect Ratio

The numeric ratio of the bar’s height to the symbol’s length.

Bar Codes

They are fast, speeding both data entry and data collection, they allow instantaneous, real-time data capture and exchange. Bar codes are also accurate. Studies show that the entry and read error rates when using bar code technology is approximately one error in one million characters, vs. one error per every 300 characters using manual key entry.


The area surrounding a printed symbol, including the spaces and quiet zones. Also referred to as the Substrate.

Bar Code Character

A group of bars and spaces that represent an individual character (alpha, numeric or other ASCII character).

Bar Code Density

A measure of the number of characters which may be printed per lineal inch. This measure normally does not include the space required for the “Quiet Zone”.

Bearer Bars

A minimum of two parallel bars running the length of the top and bottom edge of a bar code. Bearer bars, if used, reduce the probability of a misread when a skewed scanning beam enters and/or leaves the symbol through the top or bottom.


Characteristic of most bar code symbologies which permits scanning of the bar code symbol in either the left-to-right or right-to-left direction.

Character Set

The set of characters permitted within a particular bar code symbology type.

Check Character

A character used to check the integrity of the preceding bar code symbol. A check character is normally found at the end of the data encoded within the bar code.

Clear Area

The area which precedes the first printed bar of the start character, and follows the last printed bar of the stop character. This area should be free from any printing, and should be of the same color and reflectance as the background of bar code symbol. The clear area should be ten times the width of the narrowest element in the bar code, or 0.25 inch minimum. Clear Area is also known as Quiet Zone.

Code 39

An alphanumeric bar code that can encode decimal numbers, the upper case alphabet, and the following special symbols: _ . * $ / % + Also see Extended Code 39.

Codabar ÔÇö A01234B

Codabar is a discrete, numeric code with special characters and four different start/stop characters. Allowable data characters are (0 – 9), special characters (- $ : / . + ), and start-stop characters ( A, B, C, D )

Code 128

It’s a continuous, multilevel, full ASCII code. There are three types of code 128 encoding. Type A provides the character set of all upper case alphanumeric characters plus all of the ASCII control characters. Type B provides the character set of all upper and lower case alphanumeric characters. Type C provides increased density for numeric encoding with double density numeric characters for all number pairs from 00 to 99.

Code 11

A numeric, high density code.

Code 93

A continuous, multilevel, full ASCII bar code.

Color Scheme

Scanners read bar codes by using red light to recognize the contrast between the bars and spaces of the symbol. Colors that will scan effectively need to be chosen. Black bars against a white background are the safest choice, but other combinations will also work. Quiet Zone: The margins around the bar codes are vital, they enable the scanner to identify the beginning and the end of the bar code.

Data Identifier

A character (or set of characters) that uniquely defines the specific use of the data encoded in the bar code symbol following the data identifier. Also known as a Flag Character.


An electronic device which translates the electrical signals from a scanner into computer compatible data. The decoder performs checks on the electronic signal to validate it, and processes the signal through a decode algorithm designed to detect errors in the signal. The output of the decoder may drive a keyboard input to a terminal (see Keyboard Wedge Decoder) or may interface with a communications port on a computer (see Serial Decoder).

Dot Matrix

Dot matrix print technology is one of the oldest techniques used for on-site label printing. The typical dot matrix bar code printer is a modified line printer requiring pin-feed paper stock. Solenoid-driven needles strike an ink-coated nylon ribbon, transferring ink onto the paper or label. The image is built up dot-by-dot in a matrix as the needle and paper are moved relative to one another.

Direct Thermal Printing

It’s an old technology, originally designed for copiers and fax machines, that utilizes chemically coated paper. It has since been transformed into a highly successful technology for bar coding. The direct thermal printhead consists of a long, linear array of tiny resistive heating elements (about 100 to 300 per inch) that are arranged perpendicular to the paper flow. Each printhead element locally heats an area directly below it on the chemically coated paper. This produces a chemical reaction that causes a black dot to form in that area. The image is built by rows of dots that are formed as the media passes beneath the active edge of the printhead.

Demand Printer

A printer capable of creating individual documents one at a time, as needed.

Dot Size (Printer)

The size of the printed dot on a substrate in a matrix or line to form characters. Minimum dot size is determined by the size of the thermal element of the print head being used by the thermal printer. Dot size determines the X dimension. The X dimension is always a simple multiple of the dot size.

Dot Size (Scanner)

The diameter of the beam of light projected by the scanner used to read a bar code symbol. The scanner dot size should be no larger than the X dimension of the bar code symbol.


It’s an association which manages a world-wide system that allows the identification and communication of products, services, utilities, transport units and locations. It develops and maintains coding standards for all users, and has the aim of developing a global standard with the objective of providing a common language for international trade.

EAN International

It’s a voluntary, not for profit International standards association, established to meet the communication needs of its users. EAN International was founded in 1977, as a result of the initiative of European manufacturers and distributors and has expanded to cover the world. The organization has a membership of 79 Numbering Organizations covering 86 countries. The EAN/UCC system is used by more than 600, 000 companies world-wide.

EAN Bar Code (European Article Number)

The international standard or system for applying unique article numbers and bar codes to products. The EAN bar code is a numeric only code, generally encoding 13 digits (known as EAN-13), though in specific circumstances shorter codes (EAN-8) and supplementary codes are used. The North American equivalent (now technically a subset of the EAN system) is the Universal Product Code (UPC).

Extended Code 39

The full 128 character ASCII character set can be encoded by pairing Code 39 characters. Enabling Extended Code 39 causes the following characters to be output for each character pair.

FACT (Federation of Automated Coding Technology)

A bureau of AIM consisting of organizations that use and promote automatic identification among their members.

Flat Bed Scanner

A fixed scanner (used at supermarket checkouts) which can read bar code symbols at any angle in a plane parallel to or near parallel to the scanner window. Flat bed scanners are typically capable of reading bar code symbols from many different orientations. The term “Omni-Directional” scanning is referred to with this type of scanner.

Guard Bars

The auxiliary characters at both ends and center of EAN and UPC bar code symbols which provide reference points for scanning. In most cases the bars of these auxiliary characters are elongated. The guard bar function as start/stop characters; for omni-directional scanning the center guard bar (where present) acts as a stop character and the outer guard bars act as two separate start characters. There are no center guard bars on UPC-E symbols (and other less common architectures).

Light Pen

See wand.

Human Readable

The text equivalent of the encoded information within the bar code symbol, normally printed below or above the bar code symbol, for convenience or confirmation of encoded data by humans.

Interleaved 2 of 5 code

It’s a numeric only bar code. Due to the interleaving of the characters, the number of characters in an Interleaved 2 of 5 message must be even. The check character, if used, must be included in the character count Especially adapted to the poor quality of packaging materials frequently used for trade items (corrugated cardboard), it is designed to be read by a fixed or portable bi-directional scanner.It’s a numeric only bar code. Due to the interleaving of the characters, the number of characters in an Interleaved 2 of 5 message must be even. The check character, if used, must be included in the character count Especially adapted to the poor quality of packaging materials frequently used for trade items (corrugated cardboard), it is designed to be read by a fixed or portable bi-directional scanner.

Inter-Character Space

The space between two adjacent bar code characters in a discrete code. Also called the Inter-Character Gap.

ISO (International Organization for Standardization)

It’s a worldwide federation of national standards bodies from some 100 countries, one from each country. ISO is a non-governmental organization established in 1947. The mission of ISO is to promote the development of standardization and related activities in the world with a view to facilitating the international exchange of goods and services, and to developing cooperation in the spheres of intellectual, scientific, technological and economic activity. For more information access

Keyboard Wedge Decoder

See Decoder.

Ladder Code

A bar code printed in a vertical position such that the bars can be thought of as rungs on a ladder. Contrast with Picket Fence.

LOGMARS (Logistic applications for Marking And Reading Symbols)

A Department of Defense program intended manage inventory by placing Code 39 bar code symbols on all items sold to the Federal Government.

Manufacturer Identification Number

The Manufacturer Identification Number is a six digit number assigned to a manufacturer by the UCC (Uniform Code Council). This number is found on the left side of the U.P.C. number. The number is composed of a number system character and a five digit manufacturer’s code.

Matrix Symbols

A symbol which appears as a checker board; they are most likely square in shape, and contain some form of unique “finder pattern,” which distinguishes them from others and provides a decoding reference for scanners.


One thousandth of an inch (0.001 inch), or approximately 0.0254 millimeter. Commonly used to refer to the width of bar code elements, for example, 0.013 inch would be expressed as 13 mils.

Minimum Reflectivity Difference

A white space will reflect more light than a black bar. The minimum reflectivity difference is the variance between the least amount of light reflected by the narrowest white space, and the most amount of light reflected by the widest black bar. Minimum reflectivity difference is one measure of the read-ability of the bar code symbol.


The situation which occurs when a bar code reading device detects a bar code symbol incorrectly (different than intended). A mis-read may be due to a defective symbol, to a mis-match between the reading device and the printed symbol, or to a defective reader or decoder. A mis-read may occur as as substitution error (the reader substitutes an incorrect character) or as a transposition error, or as a missing character in a character string.


The narrowest of bars, sometimes referred to as the X dimension. Wider bars and spaces are stated as multiples of this narrow bar.

Modulo Check Character(s)

The modulo check character is based on the remainder in a mathematical formula where characters within the data string are assigned weighted values, summed and then divided by the modulus. This value is then appended to the data string. Modulo check characters are used to ensure the accuracy of a data scan.

Number System Character

The first digit or left hand digit in a U.P.C., number. This digit identifies the type of manufacturer or how the bar code will be used. For example “0, 6 and 7” are generally used in the retail industry, while “3” is assigned to the health and drug manufacturing industries.


Optical Character Recognition.


Abbreviations commonly applied to the character set contained in ANSI Std. X3.17-1974 (A) and ANSI Std. X3.49-1975 (B).

ODETTE (Organization for Data Exchange by Tele-Transmission in Europe)

It’s a group that represents the interests of the automotive industry in Europe; equivalent of AIAG in America.


The property of a substrate material that minimizes show-through from the back side or the next sheet. The ratio of the reflectance with a black backing to the reflectance with a white backing. Ink opacity is the property of an ink that prevents the substrate from showing through.

Picket Fence Code

A bar code printed in a horizontal position such that the individual bars appear like the slats in a picket fence. See Ladder Code.

Print Contrast Signal (PCS)

Compares the amount of light reflected by the bars, in contrast to the amount of light reflected by the spaces in a bar code symbol. The Print Contrast Signal value is the bar reflectance expressed as a percentage of the space reflectance.

Print Quality

The measure of compliance of a bar code symbol to the requirements of dimensional tolerance, edge roughness, spots, voids, reflectance, PCS, quiet zone, and correct encoding.

Print Speed

Print speed is an important consideration if you require a high volume of labels to be printed daily or during peak cycles. That is because print speed is an element of “throughput”: the time lapsed between receipt of the print command and completion of the printing process. Throughput depends not only on printing time, but also on label formatting time: the time required to convert the program and data to an image on the label. Depending on the complexity of the label format and the printer’s ability to process this information in an efficient manner, label-formatting time can sometimes cause significant print delays, affecting a printer’s overall print speed capability. Such delays can be costly in productivity if they occur in a production environment where time and on-demand print capability are of the essence.

Print Volume

What is your daily label output? Zebra ‘s High Performance Xi Series printers are designed to operate continuously, during peak print cycles or non-stop for 24 hour cycles. Other models are better suited for lower volume, intermittent printing. Print speed is also a factor in meeting print volume requirements.

Production Volume Requirements

Based on your compliance and tracking requirements, you must then assess your projected daily, monthly and peak label volume usage. Does it justify the cost of off-site label printing or on-site, on-demand printing?

Quiet Zone

See Clear Area.


A measure of the smallest “X dimension” printable by a particular device or method. Also the measure of ability of a scanner to distinguish a bar code symbol.

SSCC (Serial Shipping Container Code)

With a secure bar code symbology, UCC/EAN-128 this combination allows all participants in the supply chain to use a common, standard solution for their individual tracking and tracing needs.


A bar code or symbol using a checking algorithm which can be independently applied to each character to guard against undetected errors.

Serial Decoder

See Decoder.


Any of the light elements between the dark bars of a bar code, which may or may not carry encoded information. The space may be formed by the substrate, or by a colored ink which is lighter in color than the bars.

Slot Reader

A bar code reading device requiring the substrate be drawn through a narrow slot to fix the position of the bar code symbol relative to the face of the bar code scanner. Typically used for scanning badges or membership cards.

Spectral Band

A specific range of wavelengths or light, from a minimum to a maximum, often named after a central value. The value of 633 nanometers is visible light, while 900 nanometers represents infrared light. Spectral band B633 includes those wavelengths (plus or minus 5 percent) of the 633 nanometer peak. Spectral band B900 includes those wavelengths (plus or minus 10 percent) of the 900 nanometer peak. The spectral band or scanning device is generally listed in bar code specifications.

STAC (Symbol Technical Advisory Committee) to the Uniform Code Council Inc.


Stacked Codes

16K, Code 49 and PDF417 are examples where a bar code symbol is broken into sections and “stacked” one upon another in order to increase the information density in the bar code symbol.

Start/Stop Characters

A distinct character or pattern of bars used at the beginning and end of each bar code symbol, which provides initial timing references and direction of read information to the decoding logic.

Thermal Transfer

Thermal transfer printers use the same basic technology as direct thermal printers, but replace the chemically coated material with a non-sensitized face stock and a special, inked ribbon. A durable, polyester ribbon film coated with dry thermal transfer ink is placed between the thermal printhead and label. The thermal printhead transfers the ink onto the label surface, where it cools and anchors to the media surface. The polyester ribbon is then peeled away, leaving behind a stable, passive image.


An executable program which is loaded into computer memory, is initialized and remains in memory awaiting a specific instruction in order to accomplish its execution. TSR stands for “Terminate and Stay Resident”. The TSR is normally a device driver intended to perform specialized functions such as driving a serial port or directing data from the serial port to the keyboard buffer.

UCC (Uniform Code Council, Inc.)

It’s the central management and information center for manufacturers, distributors and retailers participating in the U.P.C. system. This organization is not a government agency and is an administrative council which exists specifically to develop standard product and shipping container codes, control the issuing of company identification codes, provide detailed information and to coordinate the efforts of all participants. Although membership in the UCC is voluntary it is required to obtain a U.P.C. identification number.


It’s not intended to be used for data to be scanned at the point of sales in retail outlets. UCC 128 facilitates the encoding of the full 128 ASCII character set. The use of three different character sets (A, B and C), one of the most compact linear bar code symbologies. Character set C enables numeric data to be represented in a double density mode. Here, two digits are represented by only one symbol character saving valuable space. This symbology uses two independent self-checking features which improves printing and scanning reliability.

U.P.C. (Universal Product Code)

It’s a 12-digit all-numeric code that identifies the company/product combination. The code uses a six-digit number to uniquely identify each company coupled with a five-digit number to identify each of the company’s products. The combination of these eleven digits plus a check character form the 12-digit U.P.C. number which uniquely identifies one and only one item.

According to a new independent capacity study commissioned by the Uniform Code Council, Inc. (UCC), the organization will deplete its supply of new company prefixes for the 12-digit Universal Product Code (U.P.C.) numbers by the year 2005. To provide for continued expansion of the code system and the inclusion of new companies in the future, the UCC has established a sunset date for its membership to accept the 13-digit EAN-13 code as well as the U.P.C. at the point of sale no later than January 1, 2005. EAN-13 is the global counterpart of the U.P.C.

USS (Uniform Symbol Specification)

The current series of symbology specifications published by AIM; currently includes USS-I 2/5, USS-39, USS-93, USS-Codabar and USS-128.


The technical process by which a Bar Code symbol is evaluated to determine whether it meets the specification for the specified symbol.


A device that measures a symbol’s bars, spaces, quiet zones, and optical characteristics to determine whether it meets the requirements of a specific symbol. A verifier should not be confused with a bar code reader.


An area within a bar (of a bar code symbol) which is of high reflectance relative to the dark reflectance criteria, i.e. the bar or character is poorly inked, or where the intended printed area is missing. A void may cause a mis-read or cause the reader for fail to read the symbol. See Mis-Read.


A handleld reading device in the form of a pen or wand, which requires the user to make contact with the printed symbol and stroke the barcode several times in a uniform and complete fashion. If the stroke is non-uniform, or is too rapid, or too slow the wand reader will not read the bar code symbol. Many wands are being replaced with more effective and “user-friendly” reading device, such as CCD readers or Laser readers.

Wide to Narrow Ratio

The relationship of the wide to the narrow element widths, in a bar code having two element widths. Generally between 2.0 to 1 through 3.2 to 1.

X Dimension

The dimension of the narrowest element (bar or space) in a bar code symbol.

Zero Suppression

A technique used to shorten U.P.C. codes by removing zeros from the bar code in a predetermined manner.

2-Dimensional Symbology

A machine readable symbol composed of rows of encrypted data arranged in a rectangular or square pattern. The rows of data may be composed of bar code strips, “stacked” to form the two-dimensional block pattern or arranged as a checkerboard “matrix” of typically square elements. Examples of 2-dimensional symbologies are data matrix, supercode, maxicode, and PDF417.