Bar code readers are now in common use and can be seen in shops and libraries. A bar code is composed of a series of parallel adjacent vertical lines or bars of various thicknesses. The complete information about the product can be retrieved from these vertical bars. The data coded in the form of small bars are called as bar codes. The electronic device which is used to read the coded information is called bar code reader. A bar code reader is a hand held device which scans the bar code image printed on the product and converts it into ASCII code. A computer can be used to convert ASCII code. Laser beam scanning technology is used in bar code readers. The dark lines reflect less light compared to white spaces. A scanner converts the amount of light reflected into electrical pulses which is decoded into data by a decoder. This data from decoder can be sent to computer by a cable. The advantages of these devices are economical, portable and easy to use. The main limitation is difficulty in scanning images.
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