CHAPTER 1

Introduction

Bar code is a technology that ubiquitous in modern life. Widely implemented in theretail marketplace, it has also been adopted in a broad range of diverse non-retailapplications. Bar code and the equipment to print and read it is increasingly being treatedas a "commodity", but there is still significant technical innovation occurring in the field.

The term "bar code" has come to include many different forms of contrasting opticalmarks that encode information, but we will start out by looking at the traditional definitionof a bar code symbol. A conventional bar code symbol consists of a series of varying widthparallel, adjacent bars and spaces. Predetermined width patterns are used to representactual data in the symbol. A simple bar code symbol is illustrated in Figure 1-1.

Bar code can be thought of as a printed version of the Morse code, with narrow barsrepresenting dots, and wide bars representing dashes. To read the information contained ina bar code symbol, a scanning device – such as a light pen – is moved across the symbolfrom one side to the other, as shown in Figure 1-2. As the scanning device is moved acrossthe symbol, the width pattern of the bars and spaces is analyzed by the reading equipmentand the original data is recovered. Some scanning devices do not require the operator toprovide the scanning motion: an electronic scanning system or arrangement of movingoptical elements allow the symbol's bars and spaces to be sequentially examinedautomatically. More advanced equipment uses machine vision technology to "take apicture" of a symbol and decode the information directly.

Although this book's title refers to "bar code," we will broaden the scope to include otherforms of optical symbols that are specifically designed for reading by machine means.

Bar code is an automatic identification technology. It allows real-time data to becollected accurately and rapidly. Modern 2-D bar code symbologies have the ability tocontain a large amount of data that can rapidly be extracted. But bar code by itself does notsolve problems. The combination of bar code with appropriate computer hardware andapplication software creates the potential for improving performance, productivity, andultimately, profitability.

This book provides a thorough background of the technology of bar coding. It reviewsapplicable equipment and outlines selection criteria. It also presents information ontechniques and approaches to system integration and examines several applications in abroad range of industries.

CHAPTER 2

Data EntryTechniques

Computers have become an integral part of almost all business operations. They areactively used for planning, controlling, producing, tracking, and analyzing most aspects ofcommerce. The ever-decreasing cost and size of computers has allowed them to penetrate awide variety of businesses, institutions, agencies, organizations, and homes.

A piece of computer hardware by itself is not exceptionally useful. In order to beproductive, a computer must be equipped with software suitable to the particularapplication. The effectiveness of the computer hardware/software system is a function ofthe input data that is provided to it. In order to maximize the benefit from a computer,timely (ideally, real-time) and accurate data is required.

There are many data collection techniques that can be used to provide data to computers,and some of these will be reviewed in this chapter.

2.1 Manual Methods

The traditional method of entering data into a computer system has involved manuallykeying in information (using a keyboard) that has previously been gathered on sheets ofpaper. Studies show that the error rate with this technique is approximately 1 error forevery 300 characters entered. Obviously, every data transaction requires that a humanoperator be involved, so there are cost, reliability, and availability issues to be considered.

Manual keying does not provide real-time data entry, since the data being enteredusually reflects events that occurred in the past. Because data is often gathered first onpaper forms and then transcribed via keyboard, several opportunities for making data errorsexist.

2.2 Automatic Methods

To offset the disadvantages of manual entry methods, several automatic data entrytechnologies have been developed. In this...