Decoding barcode software technology

Posted by : admin | On : July 21, 2015

Every time I see a barcode reader, I think how does it work and what is the mechanism behind its functioning. Then one day I asked a software engineering about the same and I would like share those points in this blog.

Whether it is a local grocery store or a latest fashion store, barcodes are pretty much common and allow people to get good quality products at the best prices. Barcodes are typically placed on the labels of the products thus making it easy for the person at billing counter to read them using a barcode reader. A barcode reader is a hand-held device used to read barcodes using a red laser beam. Before understanding the technology, it is very much necessary to understand components of a barcode.

  • Quiet Zone: It is also called as the Clear Area and comes before the Start Character of a barcode symbol. It must be free of all printing and have the same color and reflect the same colors as the background of the barcode symbol. It should also be 10 times in width of the narrowest element in the specific barcode, amounting to 0.25 inch.
  • Start Code: This refers to the beginning of the barcode to the scanner. It is comprised of special barcode characters. These characters are stripped-off and not sent to the host.
  • Data: This indicates the actual data stored by the barcode.
  • Check Digit: This is a mathematical sum that verifies the accuracy of all other elements of the barcode. It is considered as the extra digit at the end of the barcode which verifies that the scanner read the barcode correctly. It is stripped off from the data and not sent to the host.
  • Stop Code: This indicates to the scanner where the barcode ends. They are not sent to the host but are stripped off.
  • Trailing Quiet Zone: After the Stop Character, this is another clear space without any printing.

How barcode reader works?

The scanning head throws LED light onto the barcode. Light is then reflected back away from the barcode into a photoelectric cell or a light-detecting electronic component. White parts of the barcode reflect the maximum light whereas black areas reflect the least.

The installed barcode software decodes the information given by the pulses and converts the same into zeroes and ones. These digits are then sent to the computer attached to the scanner which detects the code.

In this way, it displays all the related information on the computer screen. This is how barcode technology works.