Keyboard Wedge Barcode Scanner

The keyboard wedge barcode scanner is almost an indispensable device now, in all shops and super stores. The reason for this indispensability, is the popularity of the barcode system. Every product in the market is now branded with a barcode which has the price information, as well as the product information, encoded into it. The working and the installation of a keyboard wedge barcode scanner is a simple process. This article gives information on how a barcode scanner works and how to use a barcode scanner. Before we go into the working of a barcode scanner, let us see what do we mean by a barcode.

Barcode System

Barcodes are a series of black lines with white spacing in between. They form a symbolic, encrypted language that represents that represents alphanumeric characters. There are various codes used to encode data, which varies amongst manufacturers. The software used on a computer to read the barcode, has to have the specification of the coding standard used, so that it decrypts it correctly. The inspiration for the invention of the barcode came from the 'Morse code'. So the barcodes are like graphic Morse codes used to encode data. The widths of the black lines and white spaces and their sequences are used to define a language, that has a barcode analog symbol for every word or number. The barcode starts and ends with an extended white space, called the 'silence zone'.

Working of a Keyboard Wedge Barcode Scanner

Any book you buy or almost any other commodity has its own unique barcode. In a supermarket, when you check out, all of your billing is done by using a device which reads the pricing of each commodity, encoded in the barcode. That device is known as a keyboard wedge barcode scanner.

It is called a keyboard wedge barcode scanner, as it is 'wedged' or placed between a keyboard and the computer. The keyboard wedge scanner is attached to the computer by replacing the keyboard at its port. That is, the keyboard is unattached from its port and the scanner terminal is connected in its place. Then the keyboard is attached to the end of the scanner which has an extra connection for the purpose. In this arrangement, the keyboard continues its function normally.

The advantage of this arrangement is that the computer identifies the scanner as a keyboard. Therefore whatever data is sent by the scanner to the computer is identified as keyboard input! Of course, for this to happen, the scanner has to have a facility to read the data and convert it into ASCII code.

The technology that makes reading of barcode possible with a barcode scanner is the CCD (Charge coupled device) technology. CCD is an array of photosensitive cells, that generate electric currents and have shift registers which constitute its memory element. When the keyboard wedge barcode scanner, scans a barcode, the ambient light reflected from it, falls on the CCD. This light is of varying intensity and generates a varying current output from the photosensitive cells. An image of this varying intensity pattern is generated by the charge coupled devices, in the form of a varying voltage pattern. This pattern is then read and decrypted into numbers or alphabets by the internal programmed mechanism of the scanner.

These numbers and alphabets are then converted into the corresponding ASCII codes just like a keyboard. So the data that is read from the barcode, is interpreted as keyboard input by the computer and gets typed in whichever software application is open for billing purpose. Like a keyboard input, it gets entered, wherever the cursor is placed in the application.

The disadvantage of a keyboard wedge barcode scanner is that it cannot process or separate the read data, from the barcode. It serves the decoded data without any changes. One cannot parse the data, classify it or place it in separate boxes. So it is only good for general applications. If one wants an advanced pre-processing of decoded data, then some other type of barcode scanner must be used.

Thus, the keyboard wedge barcode scanner is a simple device, that you can use in your shop or store, to read barcodes for you and identify prices. With this scanner and the software that reads and processes its output, you have a complete billing solution for your shop!