Symbology - A two dimensional arrangement of contrasting marks
encoding information in accordance to specific rules. The resolution
of the symbol's markings is substantially equal in two orthogonal
2-D Stacked Symbology - A symbology consisting
of 2 or more adjacen and associated rows of varying-width parallel
bars and spaces. All of the rows in a symbol are the same
2-Dimensional Bar Code - Two dimensional
symbology composed of rows of data arranged in a rectangular or
square pattern. The rows of data are stacked onto each other to
encode an array of data.
Accuracy - The determination
of whether any element width or intercharacter gap width (if
applicable) differs from its nominal width by more than the printing
AIM - Automatic Identification
Manufacturers organization supported by manufacturers and suppliers
of automatic identification products and services.
an automatic identification system, the relative position and
orientation of a scanner to the symbol.
ANSI - The
American National Standards Institute, a nongovernmental
organization responsible for the development of voluntary
Aperture - The opening in an optical system
that establishes he field of view.
ASCII - The
character set and code described in American national Standard Code
for Information Interchange, ANSI X3.4-1977. Each ANCII character is
encoded with 7 bits. The ASCII character set is used for information
interchange between data processing systems, communication systems,
and associated equipment. The ASCII set consists of both control and
Aspect Ratio -In a bar code
symbol, the ratio of bar height to symbol
Autodiscrimination - Capability of reading and
decoding more than one bar code symbology in a single piece of
Background Reflectance - Expressed as a percent; the simple
arithmetic average of the background reflectance from at least five
different points on the sheet.
Background - The spaces, quiet zones and area
surrounding a printed symbol.
Bar - The darker element
of a printed bar code symbol.
Bar Code - An automatic
identification technology that encodes information into an array of
adjacent varying width parallel rectangular bars and
Bar Code Character - A single group of bars
and spaces that represents a specific number (often one) of numbers,
letters, punctuation marks or other symbols. This is the smallest
subset of a bar code symbol that contains data.
Density - The number of data characters that can be represented
in a linear unit of measure. Bar code density is often expressed in
characters per inch.
Bar Code Label - A label that
carries a bar code symbol and is suitable to be affixed to an
Bar Code Reader - A device used to read a bar
Bar Code Symbol - See
Bar Height - See Bar Length.
Length - The bar dimension perpendicular to the bar width. Also
called height. Scanning is performed in an axis perpendicular to the
Bar Width - The thickness of a bar
measured from the edge closest to the symbol start character to the
trailing edge of the same bar.
Bar Width Reduction -
Reduction of the nominal bar width dimension on field masters or
printing plates to compensate for systematic errors in some printing
processes. Bar width reduction can have positive or negative
Blemish Percent - The Blemish Percent is an
indication of what percent of the total measured bar height has
spots or voids or is damaged with ink or toner blobs.
CCD - A Charge Coupled Device is a bar code scanner
which senses the light and dark areas of a
Character - 1. A single group of bars and
spaces that represents a specific number (usually one) of numbers,
letters, punctuation marks, or other symbols. 2. A graphic shape
representing a letter, numeral, or symbol. 3. A letter, digit, or
other symbol that is used as part of the organization, control or
representation of data.
Character Alignment - The
vertical or horizontal position of characters with respect to a
given set of reference lines.
Character Density - For
a conventional single-row bar code symbol, the number of characters
represented in the symbol divided by the total width of the symbol,
expressed as characters per unit width (as in characters per inch,
cpi). For a multi-row bar code symbol, the number of characters
represented by the symbol, expressed as characters per unit
Character Set - Those characters available for
encodation in a particular automatic identification
Check Character - Those characters
included within a string of data whose value is used for the purpose
of performing a mathematical check to ensure the accuracy of the
Check Digit - A check digit serves the same
purpose as a check character, but it may assume numeric values
Clear Area - See Quiet
Cloaking - A term used to describe placing an
electronical mask over a bar code label. It is used when there is
more than one bar code image in the field of view at the same
Codabar - A numeric only bar code consisting of
seven black and white bars. Two bars are wide (Code
Code 128 - A alphanumeric bar code capable of
encoding all 128 ASCII characters.
Code 16K -
Multi-row (stacked) code in which each symbol can have between two
and sixteen rows or stacks. Each row is separated by a one module
separator bar, and consists of 18 bars and 17 spaces. The code is
analogous to sentences in a paragraph.
Code 39 - A
full alphanumeric bar code consisting of nine black and white bars.
Three bars are wide (Code 3 of 9). Code 39 is the most frequently
used symbology in industrial bar code systems
Coercivity - Value of the opposing magnetic
intensity that must be applied to a material to remove the residual
magnetism when it has been magnetized to
Concatenation - The ability of a reading
system to join together the data from multiple symbols and interpret
it as a single message.
Continuous Code - A bar code
symbology where all spaces within the symbol are parts of
characters, e.g., Interleaved 2 of 5. There is no intercharacter gap
in a continuous code.
CPS - Characters Per
Cathode Ray Tube. Also called a terminal or monitor.
Matrix - Variable size two dimensional matrix symbology that is
inherently omnidirectional. Data Matrix has a high degree error
correction capability and is used primarily for part marking and
Decode - Each bar code symbology has a
specific decode algorithm. If a symbol is decoded correctly, it will
receive an "A" grade. If not, it will receive an "F" grade. The ANSI
grade of Decode checks for: -Valid Characters -Correct start and
stop characters (patterns) -Correct check digits (when applicable)
-Legal quiet zones (i.e. blank space before and after a bar code)
-Correct number and format of characters
Decoder - As
part of a bar code reading system, the electronic package that
receives the signals from the scanner, performs the algorithm to
interpret the signals into meaningful data, and provides the
interface to other devices.
Defects - Defects are
voids found in the bars or spots found in the spaces and quiet zones
of a bar code symbol. Defects are measured by the ratio between the
maximum element reflectance nonuniformity and symbol contrast.
Element reflectance nonuniformity is the difference in reflectance
between the highest peak and lowest value within an element (bar or
space) of the bar code symbol. When an element consists of a single
peak or valley, its reflectance nonuniformity is zero. Defects =
ERNmax/SC. The grade for Defects is determined by: A(4.0)<=.15
B(3.0)<=.20 C(2.0)<=.25 D(1.0)<=.30
Density - See Character
Depth of Field - The distance between the
maximum and minimum plane in which a code reader is capable of
reading symbols of a specified X dimension.
Reflection - The component of reflected light that emanates in
all directions from the reflecting surface.
Thermal - A process in which a set of pins on a printhead are
selectively heated onto heat-sensitive paper (or label stock). In
turn, the paper turns dark and a bar code is formed. Over time, a
Direct Thermal image will eventually fade. Also known as Thermal
Discrete Code - A bar code symbology where
the spaces between characters (interchanger gap) are not part of the
code, e.g., Code 39.
DPI - Dots Per
EAN - European Article Numbering system, the
international standard bar code for retail food
Edge Contrast Minimum (Ecmin) - The Edge
Contrast Minimum is the minimum difference in the reflectance value
between any particular space (including quiet zones) and its
adjoining bar within a bar code symbol. The smallest difference that
is found across a bar code symbol must be at least
Edge Determination - In order to calculate the
grade of Edge Determination, the Global Threshold (GT) of the bar
code must first be determine: GT = Rmin + (SC/2). Once the Global
Threshold is established, the elements of a bar code are defined as:
BAR: Any point on the SRP at or below the Global Threshold. SPACE:
Any point on the SRP above the Global Threshold. If the number of
elements for a bar code symbology are invalid, the symbol will
receive an "F"grade for Edge Determination.
In a bar code symbol, a single bar or space.
Federal Communication Commission.
FFO - Fixed Focus
Optics technology uses a small aperture and non-moving lenses to
digitize an image over a wider range of distance than the
traditional CCD reader.
Film Master - A photographic
film representation of a specific bar code or OCR symbol from which
a printing plate is produces.
First Read Rate - The
ratio of the number of successful reads on the first scanning
attempt to the number of attempts. Commonly expressed as a
percentage. Abbreviated as FRR.
Font - A specific size
and style of printer's type.
Font-Independent OCR -
Optical character recognition by generalized algorithms allowing
wide ranges of character fonts. In the most general case, this
extends to bar code patterns as well.
- See definition of GT.
GT - Abbreviation for Global
Threshold. The global threshold is a position located half way
between the highest recorded reflectance and the lowest recorded
reflectance on a scan reflectance profile.
- The bars that are at both ends and center of a UPC and EAN symbol.
They provide reference points for scanning, serving a function
similar to start/stop codes.
GUI - Graphical User
Interface. The visual design of a software
Height - This number indicates how many
horizontal scan lines of the video camera detected bar code data. It
is figured out by determining the difference between the lowest scan
line number ever decoded and the highest scan line ever decoded. A
standard UPC label will have a height of 140. This figure can be
found on the SETUP SCREEN.
Helium Neon Laser - A type
of laser commonly used in bar code scanners. It emits coherent red
light in a wavelength of 633 nanometers.
Code - A bar code or symbol presented in such a manner that its
overall length dimension is parallel to the horizon. The bars are
presented in an array which look like a picket fence.
25 - See Interleaved 2 of 5.
IAN - Industrial
Article Numbering. See EAN.
Ideal - It is a number
which indicates the ideal IRIS setting in a camera based reader.
In Spec - A term used to describe a bar code symbol
that has been printed in complete compliance with the symbology
specification's requirements for element widths and tolerances,
element reflectivity and uniformity, spots, voids, and edge
Infrared Laser Diode - An invisible light
beam used in some bar code readers to scan a bar code that is
invisible to the human eye. This technology is used specifically to
prohibit people from visually reading the bar code. Analogous to
night vision goggles.
Input Device - That portion of a
bar code reading system that employs electro-optical techniques to
determine the localized reflectivity of a
Intercharacter Gap - The space between two
adjacent bar code characters in a discrete code. For example, the
space between two characters in Code 39.
Interleaved 2 of
5 - A numeric only bar code consisting of five bars. Two bars
are wide, three are narrow. Used generally in industrial and master
Interleaved Bar Code - A bar code in
which characters are paired together using bars to represent the
first character and spaces to represent the second, i.e.,
Interleaved 2 of 5 (See Continuous Code).
Iris - [Vmax
- Vmin = Iris] This number is an indication of how much light is
being allowed on to the surface of the CCD element of the video
camera. It is always equal to Vmax minus Vmin. It can be found on
the SETUP SCREEN.
Iso - The international standards
organization,k and international nongovernmental organization
responsible for the development of voluntary
Label Repeat - The distance between the top
of a bar code image to the top of the next bar code image.
Ladder Barcode - See Vertical Bar
Laser Scanner - An optical bar code reading
device using a low energy laser light beam as is source of
LCD - Liquid Crystal
LED - Light emitting diode. A semiconductor
that produces light at a wavelength determined by its chemical
composition. The light source often used in light
Light Pen - In a bar code system, a hand-held
scanning wand that is used as a contact bar code reader held in the
hand. (See Wand Scanner.)
LPM - Lines per
MaxiCode - Fixed size two dimensional
symbology having elements arranged around a unique circular finder
pattern. MaxiCode is omnidirectional and is primarily used for
freight sortation and tracking.
MICR - Magnetic Ink
Character Recognition style printing on the bottom of personal and
Mil - One one-thousandth of an inch
(0.001"). Bar code densities are commonly referred to as number of
mils (i.e. 10 mils).
Minimum Reflectance (Rmin) - The
reflectance value of the darkest bar within a bar code symbol must
be less than or equal to half the reflectance of the lightest
Misread - A condition that occurs when the data
output of a reader does not agree with the data encoded in the bar
Modulation relates to how a
scanner "sees" wide elements in relationship to narrow elements, as
represented by reflectance values in the Scan Reflectance Profile.
Scanners typically "see" narrow spaces as being less reflective than
wide spaces. The closer the grades of Edge Contrast Minimum and
Symbol Contrast, the higher the Modulation grade. MOD = ECmin/SC.
The grade for Modulation is determined by: A(4.0)>=.70
B(3.0)>=.60 C(2.0)>=.50 D(1.0)>=.40
Module - The narrowest nominal width unit
of measure in a bar code.
Modulo Check Digit or
Character - See Check Character.
Moving Beam Bar Code
Reader - A scanning device where scanning motion is achieved by
mechanically or electronically moving the optical
MRD - Minimum Reflectance Differential. A
method that is used to determine if there is an adequate difference
between absorbed and reflected light.
Plessey - Modified Plessey Code is a pulse width modulated bar
code used primarily for making retail shelving.
The ratio between the widths of wide elements and narrow elements in
a 2-width symbology.
Nanometer - A unit of measure
used to define the wavelength of light. Equal to 10-9
Narrow bar - 1. An indication of the bar width
in nanoseconds. 2. This generally refers to the narrowest bar in a
Nominal - The exact (or ideal) intended
value for a specified parameter. Tolerances are specified as
positive and negative deviations from this
Non-Read - In a bar code system, the absence of
data at the scanner output after an attempted scan due to no code,
defective code, scanner failure or operator
Numeric - A character set that includes only
OCR - Optical Character Recognition is a
technology designed specifically to read certain stylized fonts
(such as OCR-A and OCR-B) containing the full alphanumeric character
set. The term OCR is also used when translating and inputting other
stylized fonts (such as Courier) or text found in magazines and
newspapers into a computer. This technology is also referred to as
Intelligent Character Recognition (ICR).
OCR - A - An
abbreviation commonly applied to the character set contained in ANSI
OCR - B - An abbreviation
commonly applied to the character set contained in ANSI Standard
Omnidirectional - A scanner that can read
in both horizontal and vertical label positions, or any position
between horizonal and vertical.
- Two oversquare bar codes, placed perpendicular to each other. A
common application is the airline baggage
Opacity - The optical property of a substrate
material that quantifies the 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
Optical throw - The region between the
scanner and the readable depth of field.
The alignment of a bar code symbol with respect to horizontal. Two
possible orientations are horizontal with vertical bars and spaces
(picket fence) and vertical with horizontal bars and spaces
Overhead - Overhead - In a bar code system,
the fixed number of characters required for start, stop and checking
in a given symbol. For example, a symbol requiring a start/stop and
2 check characters contains 4 characters of overhead. Thus to encode
3 characters, 7 characters are required to be
Oversquare - A label in which the height is
greater than the length.
PCS - Print Contrast Signal.
A measurement of the ratio of the reflectivities between the bars
and spaces of a symbol, commonly expressed in percent. PCS is
calculated as: RL-RD/RL x 100%, where RL = reflectivity of the light
elements and RD = reflectivity of the dark
PDF417 - Two-dimensional bar code providing
error correction, detection and security used primarily in parcel
tracking applications and hazardous material
PDT - Portable Data Terminal. Handheld
terminal capable of storing and recording data that is captured
remotely and later transmitted into a computer.
Fence Code - See Horizontal Bar Code.
Rotation of a bar code symbol about an axis parallel to the
direction of the bars.
PostNet - Postal Numeric
Encoding Technique used to encode ZIP code information on letter
mail. PostNet uses redundant information within a compact bar code
format to provide error detection capability and a significant
degree of error correction capability.
- See PCS.
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
Printhead - The device on a direct thermal
or thermal transfer printer containing the heating element that
causes that image to be transferred to the
Quiet Zone - A clear space, containing no
dark marks, that precedes the start character of a bar code symbol
and follows the stop characters. Sometimes called the "clear
Raster - More than one scan line in two or more
horizontal dimensions to allow reading of bar codes in different
Ratio The ratio between wide elements and narrow
elements. It is used to measure decodability properly. This applies
to symbologies such as Code 39 Codabar and, 2 of 5.
window - The region within which the scanner is capable of
reading bar code. The read window is defined by the scanner's scan
width, focal point, and depth of field.
Reader - See
Bar Code Reader.
Reduced Scale Symbology - See
Reflectance - The ratio of the amount of light of
a specified wavelength or series of wavelengths reflected from a
test surface to the amount of light reflected from a Barium Oxide or
Magnesium Oxide standard under similar illumination
Resolution - In a bar code system, the
narrowest element dimension that can be distinguished by a
particular reading device or printed with a particular device or
RF - Radio Frequency. Wireless communication
technology using electromagnetic waves to transmit and receive data.
RF provides real-time access to a host
Ribbon - Material used with thermal transfer
printers producing visible marks on a label (or substrate). A
printhead is heated and the ribbon is burned on the label stock
producing the bar code.
RSS-14 - Encodes the full 14
digit EAN.UCC item identification in a linear
RS-232 - The most common communication
interface (e.g. serial (COM) port) standard using a DTE (Data
Terminal Equipment) and DCE (Data Communications Equipment)
interface. Also known as serial communication.
- The second most common communication interface standard which
extends beyond the 100 feet limitation of RS-232 data communication
supporting a maximum distance of 4000 feet.
RSS - A
bar code symbology that contains three linear symbologies to be used
with the EAN.UCC system. The use of the symbologies are restricted
and subject to compliance with the EAN International (EAN) and
Uniform Code Council Inc (UCC) rules and registration
RSS Expanded - Encodes EAN.UCC item
identification plus supplementary AI element strings such as weight
and "best before" date in a linear symbology. RSS expanded can also
be pinted in multiple rows as a stacked symbol.
Limited - Encodes the 14-digit EAN.UCC item identification with
indicator digits of zero or one in a linear symbol for use on small
RSS Stacked - A version of the RSS-14 symbology
that is stacked in two rows and is used when the normal symbol would
be too wide for the application. It comes in two versions, a
truncated version used for small item marking applications and a
taller omnidirectional version which is designed to be read by
omnidirectional scanners. RSS expanded can also be pinted in
multiple rows as a stacked symbol.
Scan line - The
beam of light that reads across the bar code for
Scan rate - Scanner speed, in scans per
Scan Reflectance Profile (SRP) - A map (or
plot) of the localized symbol reflectivity as a measuring aperture
is scanned across the symbol along a specific path. The "peaks" of
the SRP indicate the largest value of reflectance (the spaces in the
bar code) and the "valleys" of the SRP indicate the smallest value
of reflectance (the bars in the bar code).
An electronic device that electro-optically converts optical
information into electrical signals.
Self-Checking - A
symbology is termed self-checking if a single printing defect will
not cause a character to be transposed into another valid character
in the same symbology.
Serial Communication - See
Skew - Rotation of a bar code symbol about an
axis parallel to the symbols length.
Skew - The
rotation of a bar code symbol about an axis parallel to the
Space - The lighter element of a bar code
usually formed by the background between bars.
Width - The thickness of a space measured from the edge closest
to the symbol start character to the trailing edge of the same
Spectral Response - The variation in
sensitivity of a reading device or the variation in reflectivity of
a test surface to light of different wavelengths.
Reflection - The mirror-like reflection of light from a
Specular reflection zone - A narrow zone in
front of the scanner in which direct, non-diffused light blinds the
Spot - 1. The undesirable presence of ink or
dirt in a space. 2. The area on a bar code symbol that is being
examined by an input device at any given point of
SRP - See scan reflectance
Stack Code - Two-dimensional bar code where
linear bar codes are stacked one upon another and are printed in a
rectangular shape to achieve the most efficient use of label
Standard - A set of rules, specifications,
instructions, or directions for printing, labeling, scanning, etc.
bar coded information.
Start/Stop Character or Pattern
- A special bar code character that provides the scanner with start
and stop reading instructions as well as scanning direction
indicator. The start character is normally at the left-hand end of a
horizontally oriented symbol. The stop character is normally at the
right-hand end of a horizontally oriented
Substitution Error Rate (SER) - The rate of
occurrence of incorrect characters from an automatic identification
Substrate - The surface on which a bar code
symbol is printed.
Symbol - A combination of bar code
characters including start/stop characters, quiet zones, data
characters, and check characters required by a particular symbology,
that forms a complete, scannable entity.
(SC) - The difference between the largest (including quiet
zones) and smallest reflectance values within a Scan Reflectance
Profile. SC = R,ax - Rmin. The grade for Symbol Contrast is
determined by: A (4.0)>=70% B (3.0)>=55% C(2.0)>=40%
Symbol Density - See Bar
Symbol Length - The distance between the
outside edges of the quiet zones on the two ends of a bar code
Target - This number correlates vision based
bar code data to wand bar code data. A target value will increase or
decrease due to differences in X dimensions, bar heights, or
electronic noise. A full size UPC label will have a target of
Thermal - See Direct Thermal.
Transfer - A process in which a set of pins on a printhead are
selectively heated onto a ribbon and the ink from the ribbon is
burned (transferred) onto the label stock. Thermal transfer leaves a
permanent image on the label.
Tilt - Rotation of a bar
code symbol about an axis perpendicular to the
Traditional OCR - The first form of
2-dimensional OCR developed, using the stylized OCR-A and OCR-B
Trigger - A method for informing the
scanner/decoder of when to look for bar codes. This can be an
external sensor device or a host-generated signal.
- Uniform Code Council is an organization which administers the UPC
and other retail standards.
UCS - Uniform Container
Uniform Code Council (UCC) - Previously the
Uniform Product Code Council, the organization that administers the
UPC and other retail standards.
UPC - Universal
Product Code, the standard bar code symbol for retail food packages
in the United States.
UPC-A - A UPC symbol encoding a
number system character, 10 digits of data, and a check
UPC-E - A UPC symbol encoding 6 digits of data
in an arrangement that occupies less area than a UPC-A symbol. Also
called a "zero-suppressed" symbol because a 10
digit UPC-A code
can be compressed to a 6 digit UPC-E format by suppressing redundant
USS - Uniform Symbol Specification. The current
series of symbology specifications published by AIM; currently
include USS-Interleaved 2 of 5, USS-39, USS-93, USS-Codabar, and
Verifier - A device which measures the
characteristics of a bar code including the contrast, reflectance,
modulation, and compliance with the parameters of the bar code
symbology to ANSI/ISO standards.
Vertical Bar Code - A
code pattern presented in such orientation that the axis of the
symbol from start to stop is perpendicular to the horizon. The
individual bars are in an array appearing as rungs of a
Visible Laser Diode - Used in most handheld
scanners to project a visible red light for scanning human readable
Vmax - This number indicates a value for
the highest point of reflectivity in the image of a bar code as used
in camera based systems.
Vmin - This number indicates
a value for the lowest point of reflectivity in the image of a bar
code label as used in camera based systems.
Void - The
undesirable absence of ink in a printed bar.
See Wand Scanner.
Wand Scanner - A handheld scanning
device used as a contact bar code or OCR reader.
- A hardware device or software program (Software Wedge) which uses
a scanner for input and sends data directly into an application by
emulating a keyboard stroke. A wedge (hardware wedge) is an external
device and plugs between the keyboard and
WYSIWYG - "What You See Is What You Get" is
a term used to describe the presentation of the printable output
viewed as is on the terminal.
X Dimension - The
nominal width dimension of the narrow bars and spaces in a bar code
symbol. The narrowest element of a barcode image.
Dimension - The dimension of the narrowest bar in a bar
Z Dimension - The achieved width of the narrow
elements, calculated as the average of the average narrow bar width
and the average narrow space width.