barcode guide

Barcode Guide

Bar Codes and Variable Data

Unlimited Applications– Inventory Control– Sorting, Tracking– Verification– Quality Control– Automated Warehousing– Shop Floor Control– Product Identification– Addressing

What is a Bar Code?

A Pattern of dark and light areas– Can be bars (Linear) or cells (2D)

The pattern represents the encoded information

May contain letters, numbers, characters or a mix

Why use a Bar Code?

Accurate Eliminate data entry errors

– Errors due to bar codes: less than 0.001%– Coded information errors: 1 every 10,000,000

characters– Manual information errors: 1 every 100

characters Fast

– Read and decode infinitely faster than manually

Easy and cheap to produce

Bar Code Terminology

Bars and Spaces– The elements of the bar code. Made up of

narrow and wide lines Human Readable

– The ASCII interpretation of the coded information

– Can be printed near the bar code for verification

Quiet Zone– Clear area before and after the printed code– Allows scanner to “calibrate” to the image


– Quiet zone is required to read data– Minimum quiet zone can vary with different

symbology

Discrete Bar Code– Unique pattern for each character. Can be

manually decoded


Continuous Bar Code– Bar patterns overlap. Each character’s symbol

relates to the ones around it– Can not be easily manually decoded


Check Digit– Confirms integrity of the encoded and decoded

data– A formula uses the bar code data to generate a

digit which is then added to the encoded information

– The reader calculates a check digit based on what is decoded and compares this number to the encoded number


Aspect Ratio– The ratio of Bar Height to Symbol Length

Code Density– Number of data characters which can be

encoded in a linear inch (characters/inch)

Message Overhead– Space occupied by start, stop and check digit

symbols. Increase the size of the barcode


Bar Width– Thickness of bar measured from the edge

closest to the start character to the edge farthest from the start character

Bar Length (Bar Height)– Dimension perpendicular to the bar width

Bi-Directional– Symbol type has no defined read direction– Can be decoded in either direction


Character– A single group of bars and spaces

representing a single element of data– A graphic shape representing a letter, numeral

or symbol

Character Set– Group of valid symbols which can be encoded

in a given bar code type


Data Identifier– Message prefixes, conforming to standards

that are incorporated in a bar code that define the category or use of the data that follows

Decoder– A device that uses algorithms to interpret the

signals set by the scanner and generate meaningful data

Scanner– A device that reads the bar code


Depth of field– The distance between the minimum and

maximum read distance from the scanner to the bar code

EAN– European Article Numbering System– International standard for product coding

UPC– Universal Product Code– U.S. standard for retail package coding


First Read Rate– Percentage of correct readings obtained in one

pass of the scanner

Fixed Beam Scanner– Scanner reading in a fixed plane– Requires more precise code placement

Rastering Scanner– Scan line sweeps along the bar height– Code placement does not need to be as

precise

Horizontal Bar Code (Picket Fence)– Bars are presented so the bar length is in the

direction of travel

Vertical Bar Code (Ladder, Rotated)– Bars are presented so the bar width is in the

direction of travel



Inter Character Gap– The space between two adjacent characters in

a discrete bar code

Interleaved Bar Code– Characters are paired together using bars to

represent the first character and spaces to represent the second

– Increases bar code density

Misread– Output of reader does not match encoded data


No-Read– Absence of scanner output due to no code,

defective code, scanner failure or operator error

OCR-A and -B– Character font set used in Optical Character

Recognition and automatic identification– Both human and machine readable– Defined by ANSI standards


Optical Throw– Minimum distance from the scanner to the

code for successful reading

Read Rate– Ratio of successful first scan reads to the total

number of read attempts

Reflectance– The light reflected by the white spaces– This is what the scanner actually reads


Resolution– The narrowest element division which can be

distinguished by a particular scanner

Self Checking– A code that uses a checking algorithm which

can be independently applied to each character to guard against errors

Error Checking & Correction (ECC)– A self checking code whose algorithm can fix

errors in the encoding or decoding of data


Space– Light element of a bar code– Usually formed by the substrate

Stacked Code– Long symbol is broken into sections and

stacked on itself similar to sentences in a paragraph

– Code 49 and 16K are examples of this type


Start-Stop Character– A special character which helps the scanner

decode the symbol– Start character is normally at the left end of a

horizontally oriented symbol, the stop is normally at the right

ISBN – International Standard Book Number– Unique number to identify books, audio and

video products and software


ISSN – International Standard Serial Number– Unique number to identify serial publications

such as magazines, newspapers, etc.

Selecting A Bar Code

Amount and Type of Characters encoded Quality Available Space Industry Standards How and by whom it will be decoded

– Linear codes can be read by a simple scanner– 2D codes may require a more expensive

imager

Linear Symbologies

Pros– Well established, common codes– Numerous different formats to choose from– Fast and inexpensive reading and decoding– Can include human readable interpretation

Cons– Limited data capacity– Can be space prohibitive– Type of data encoded can be limited by symbol

UPC

Universal Product Code First widely accepted bar code symbol Now a subset of the EAN symbology Fixed in length Numbers only Continuous symbol with four element

widths Number is unique and is registered to a

particular product and packaging

UPC-A

10 digits and two overhead digits First overhead digit is the type of product Second overhead digit is the check digit 5 digits identify the manufacturer, 5

identify the product

UPC-E

Similar to UPC-A Zero digits are dropped, making the code

smaller

Other UPC

UPC-B– 11 digits + 1 Overhead, no check digit

UPC-C– 12 digits + 2 Overhead

UPC-D– Variable length– At least 10 digits + 2 Overhead

EAN

European Article Numbering Code 8 and 13 are similar to UPC codes with the

addition of “Flag” digits Flag digits identify the country where the

product identification number was issued Flag digits do not determine where the

product is manufactured

EAN-8

Two Flag digits, five data digits and 1 check digit

EAN-13

Most common EAN symbol Identical to UPC-A except for Flag Digit

Supplementals

UPC and EAN 8 and 13 can have a supplemental bar code attached to carry additional information

EAN13+5

UPC-A+5

UPC-E+5

EAN-128

Extremely versatile symbol for package ID Application Identifiers determine the

purpose of the data following (Serial Number, Weight, Box Dimensions, etc.)

Same as Code 128 except for the addition of Identifiers

Code 128

General purpose alphanumeric and extended ASCII

Reference symbology for UCC Serial Shipping Container Symbol

Same as EAN-128 without Application Identifiers

Codabar

All numeric data Four unique stop/start characters to

convey additional information Optional check digit

Code 39

Most used symbol for inventory and shipping

Alphanumeric data set Extended Code 39 allows upper and lower

case characters and punctuation Most popular symbol outside of retail

(UPC) industry

Interleaved 2 of 5 (ITF)

Mainly used in the distribution industry for coding corrugated cartons

Numeric only Must be an even number of digits Continuous bar code, characters overlap

ITF-14

UPC Shipping Container Symbol Used on cartons, cases or pallets of UPC

or EAN coded products 14 digit ITF symbol Indicates the package type, quantity in

carton and UPC of packaged item

Pharmacode

Security Verification System for Pharmaceutical Industry– Insures that leaflet, label, container, carton,

contents and other packing materials match and are correct

Postnet

Used by the US Postal Service to sort mail Evenly spaced bars of two different

heights Contains a 5 (zip), 9 (zip+4), or 11 (delivery

point code) digit routing code

2D Stacked Symbologies

Pros– More data in the same amount of space as

linear codes

Cons– Still require larger area for the code– Require an imager or rastering scanner for

reading– Human readable interpretation is not available

Code 49

High information density of full ASCII set

Code 16K

High information density of full ASCII set Double density encoding of numeric data Capable of handing extended ASCII

PDF417

Easily decoded by CCD or laser scanner Selectable levels of error correction Able to encode extended ASCII set Thousands of characters capacity

Micro PDF417

Similar to PDF417 Smaller data capacity than PDF417 Limited set of symbol sizes and error

correction levels

2D Matrix Symbologies

Pros– Extremely small area for amount of data

encoded– Unobtrusive on most products adds aesthetic

values for consumer products

Cons– Expensive imaging scanners required– Can be slower to decode– Error correction and detection is essential due

to the complexity of the code

3-DI

Proprietary Code Suited for shiny, curved metal surfaces

Array Tag

Proprietary Code Can be read at distances up to 50 meters Primary use is for logs and lumber

DataGlyphs

Proprietary Code Tolerant to ink marks, bad copies, staples

etc. Can be used as a logo or tint behind text

or graphics

Dot Code A (Philips Dot Code)

Designed for low precision marking systems

Up to 12x12 matrix allows up to 42 billion, billion, billion, billion (a big number) individual items to be uniquely coded

Used on laboratory glassware and laundry

MaxiCode

Originally called UPSCode About 100 characters in a 1”x1” square Can still be read with up to 25% of the

code destroyed Primarily used by United Parcel Service

MiniCode

Proprietary code Patented method of encoding low

resolution (tracking/sortation) and high resolution (manifest information) data

Data Matrix ECC 200

Up to 3116 characters in a 144x144 matrix High density, very small code Very easy to scan under a variety of

conditions Being adopted as standard in a variety of

industry groups

Aztec Code

Public Domain 12 - 3832 characters, 15x15 – 151x151 Easy printing and decoding

QR Code

Quick Response Code Public Domain code Up to 7366 characters Capable of handling Japanese Kanji and

Kana characters

Snowflake

Owned by Videojet Proprietary, pay per use code

Composite Bar Codes

Two Symbols Printed in close proximity Data is linked between the two Typically one linear and one stacked or

matrix symbol Used in applications that require different

parts of data to be used at different times

Bar Code Quick Reference

Barcode Type Character Set Length Checksum Applications/Comments

EAN-13 Linear Numbers Only12 data digits and 1 check digit; 2 or 5 digit supplement optional Required Retail product marking world-wide

EAN-8 Linear Numbers Only RequiredRetail product marking world-wide; compressed code for products with limited label space

EAN Bookland Linear Numbers Only RequiredSpecial use of the EAN-13 symbol to encode ISBN number on books

UPC-A Linear Numbers Only11 data digits and 1 check digit; 2 or 5 digit supplemental optional Required Retail product marking in USA and Canada

UPC-E Linear Numbers Only RequiredRetail product in USA and Canada; compressed code for products with limited label space

UPC Shipping Container Code

Special use of the Interleaved 2 of 5 code to mark shipping cartons containing UPC encoded products

(ITF-14) (see also SCC-14)UCC/EAN Shipping Container Code

Special use of Code 128 to mark shipping cartons containing UPC encoded products

(SCC-14) (see also ITF-14)1 Required;2 Recommended

Interleaved 2 of 5 Linear Numbers Only Variable OptionalVery compact encodes digits in pairs so total length must be even number of digits

Industrial 2 of 5 Linear Numbers Only Variable None defined Older type of codeStandard 2 of 5 Linear Numbers Only Variable None defined Older type of codeCodabar Numbers: 0-9;(USD-4, NW-7, 2 of 7) Symbols: - : . $ / +

Start/Stop Characters: A, B, C, D, E, *, N, or T

Plessey Linear Numbers Only Variable Required Grocery store shelf tagsLinear Variable None defined Older code; often used in libraries and blood banks

Code 11 Linear Numbers Only Variable

Linear Numbers Only 13 digits and 1 check digit Required

Linear Numbers Only 13 data digits and 1 check digit Required

Bar Code Quick Reference (Cont.)

OPC(Optical Industry Association)

Bar Height USA postal codeEncoding (ZIP code)

Uppercase letters A-Z;Numbers 0-9;Space - . $ / + %Uppercase letters A-Z;Numbers 0-9;Space - . $ / + %

Extended Code 39 LinearAll ASCII characters and control codes Variable Optional

Uses pairs of characters to encode non-standard symbols; wasteful of space

Code 128 LinearAll ASCII characters and control codes Variable Required Widely used; excellent for many applications

UCC/EAN-128 LinearAll ASCII characters and control codes Variable Required

Special ise of Code 128 which defines data formats for commerce

Uppercase letters A-Z;Numbers 0-9;Space - . $ / + %

PDF-417 2-D All ASCII charactersVariable, up to about 1850 ASCII or 2725 numeric characters Error correction

DataMatrix 2-D All ASCII charactersVariable, up to 2335 ASCII characters Error correction

Maxicode 2-D All ASCII characters 93 ASCII characters Error correctionDeveloped by the United Parcel Service for encoding parcel destination information for auto-sorting

QR Code 2-D All ASCII CharactersVariable, up to about 1520 ASCII or 2509 numeric charcters Error correction

LOGMARS

In very wide use for many types of applications

Code 93 Linear Variable OptionalA more compact cousin of Code 39, not as widely in use

Code 39 Linear Variable Optional

Special use of Interleaved 2 of 5 for marking retail optical products

Postnet Numbers Only 5, 9, or 11 digits and 1 check digit Required

Linear Numbers Only 9 data digits and 1 check digit Required

Linear Variable OptionalSame as Code 39; this is the US government specification

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