Hand Held Products 3700 CCD Bar Code Basics and Scanning Tips, Closer Look At Bar Code Symbols

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A.3 Bar Code Basics and Scanning Tips

A Closer Look At Bar Code Symbols

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The illustration at the right shows a typical bar code

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

symbol. If you look at it closely, you’ll see it is

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

composed of a series of dark lines (bars) and white

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

areas (spaces) of various widths. By arranging these

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

bars and spaces in a certain order, it is possible to

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

represent, or “encode” letters, words and numbers.

 

 

 

 

 

 

 

 

 

 

 

42000

 

 

 

06200

 

 

 

 

 

 

 

 

You may also print the numbers represented by the bar code symbol on the label. These human readable characters allow you to know exactly what information the scanner is sending to the register or terminal. The human readable characters under the bar code symbol also allow you to key in information in case the bar code symbol is not readable.

The blank area located just before and just after the bar space pattern is called the “quiet zone.” It is placed on the symbol so the scanner knows exactly where the bar code begins and ends. It is important to remember where the quiet zone is located so you can scan accurately.

Bar Code Scanning

The purpose of the bar code scanner is to “read” the image formed by the bars and spaces. A signal sends the information printed on the bar code symbol to the terminal.

Several types of scanners are in use today. The most common types include the wand scanner, the laser scanner, and the CCD scanner. All scanners use optical systems which are protected by “windows” at the scanning end to read the bar code symbol. On wand scanners, the window is located in the tip. Laser and CCD scanners have a larger and more noticeable viewing “window.” It is important to keep these optics clean, because just like the lenses on reading glasses, if they become dirty, scratched or smudged, they won’t work properly.

If your scanner is attached to a decoder (or it is also a decoder), the decoder may have a beeper that will let you know when a scan has been performed properly and that the bar code has been read accurately. After you’ve scanned a symbol, listen for a single beep, (called a “good read” beep). This lets you know that the bar code information has been received by the terminal. If you don’t hear the single beep or if you hear several beeps, it means the symbol is unacceptable to the decoder, and the terminal has not received the bar code information. If that happens, try scanning the symbol again.

Before using any scanner, make sure the symbol is of good quality and that the optic area of your scanner is clean. Any dirt or specks in the bar code symbol or on the scanner optics may prevent it from reading accurately. Even a symbol that is smudged during printing, or gets wrinkled when it is applied to an object can cause a reading problem. If you can’t get a good read beep or you begin to receive error beeps, be sure to check the scanner optics and the symbol. The decoder may need to enable the beeper, either with a hardware configuration or with a software command.

A–4

CCD Operation and Bar Code Scanning

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Contents SCANTEAMR3700 CCD Disclaimer Patents Page Table of Contents Chapter Configuring the Scanteam Technical Specifications Serial Commands SummaryCCD Operation and Bar Code Scanning Ascii Conversion TableList of Tables Intended Audience PrefaceOverview of the Technical Manual Related Publications Introduction Scanteam 3700 DescriptionScanteam 3700 Hardware Description Interface Port Scanteam 3700 Software DescriptionNonvolatile Memory System Hardware Description Basic System OperationGeneral Characteristics Mechanical LayoutSingle Modular Input /Output/Power Port Audible IndicatorOperating Theory Mounting InsertsCommunications Port Scanner/Host CommunicationAsynchronous Serial Ascii Interface Hardwire Pinouts Auxiliary TriggerPower Requirements SET-UP and Installation General Preparation for UseSet-up Checklist Set-up Procedure for EvaluationPreparation Set-up Procedure To setup serial communications to the scannerInstallation in the Host Instrument Top View Examples of Scanteam 3700 Barcode Orientation Pitch or Roll Scanner Illumination Clearance Configuring the Scanteam PreparationCommand Format Command ConventionsData string Operational Commands Reset Command aDisable Decoding Command DC4 Enable Decoding Command DC2Serial Trigger Command Save Configuration Command ZSave Configuration 3C 5A 3E Serial Trigger 3C 31 3EConfiguration Commands Command Ka baud, parity, stop bits, data bits Parameter Set Communications Port Command KaOption Code ID Value Definition Command Kd enable, data ParameterScanteam 3700 Code ID Values Set Postamble Command Ke Command Ke enable, data ParameterSet Communications Protocol Command Kf Command Kf mode ParameterCommand Kg modeglobal, modeport1, modeport2, # Parameter Set Trigger Mode Command KgSet Read Timeout Command Kh Command Kk enable, data Parameter Set No Read Message Command KkSet Votes Command Km Set Code 39 Command Kp Set UPC A/E, EAN 8/13 Command Ks Command Ks enable UPC, enable EAN ParameterSet Beeper Mode Command Ku Set Code 128 Command KtSet Scan Rate Command Kv Configuration Status Query Commands Default Configuration Settings Default Operating ParametersDefault Configuration Symbology Settings SERVICE/TECHNICAL Assistance MaintenanceTroubleshooting Guide Troubleshooting HintsDiagnostic Procedure Troubleshooting ChecklistProblem Possible Cause Solution Scanteam 3700 Troubleshooting ChecklistObtaining Factory Service Product Service DepartmentOut Of Warranty Service Service Under WarrantyHelp Desk Scanteam 3700 Removal/Replacement Followed during installation ChapterService/Technical Assistance CCD Operation and BAR Code Scanning a Scanning and Decoding a Bar Code SymbolObjectives CCD Sensor LED ReflectorPeak Detectors and Comparator Microprocessor Timing SequenceBar Code Basics and Scanning Tips Closer Look At Bar Code SymbolsBar Code Scanning Optical Specifications Technical SpecificationsScanner Performance MRD minimum reflective difference 37.5% Skew AnglePitch Angle Light Source IlluminationElectrical Specifications Environmental Specifications Mechanical SpecificationsBar Code Symbol Specifications Scanteam 3700 Interface Cable To Host SystemSerial Commands Summary Command FormatCommandFormat Individual Configuration QueryKa? Kd?Configuration CommandDefault Settings Default Configuration SettingsSymbology Configuration Default Settings Serial Commands Summary Ascii Conversion Table Control Function DefinitionsAscii Conversion Table Scanteam 3700 Glossary Glossary-2 Glossary-3 Glossary-4 Glossary-5 Glossary-6 Index Scanteam Index-3 Index-4 Scanteam 3700 Limited Warranty Jordan Road Box Skaneateles Falls, New York 3700/TM Rev E