Structure of Barcode
A typical barcode consists of the following:
- Quiet Zone –The minimum required space for bar code scan-ability, preceding the Start Character of a bar code symbol. The quiet zone should be free from any printing and be the same colour and reflectance as the background of bar code symbol. The Quiet Zone should be ten times the width of the narrowest element in the bar code, or 0.25 inch minimum. Also known as Clear Area.
- Start Code –Indicates the start of the barcode. These are special bar code characters & they signify the start of data to the scanner/reader. Start characters are usually stripped-off and not transmitted to the host.
- Data –The actual data the barcode stores.
- Check Digit –Check digit (not always present) is a mathematical sum that is used to verify the accuracy of the other elements of the barcode. It is the extra digit added at the end of a bar code to allow the scanner to confirm that it read the bar code correctly. It is typically stripped from the data and not transmitted to the host.
- Stop Code – Indicates the stopping point of the barcode. These characters signify the end of data to the scanner/reader. They are also stripped-off and not transmitted to the host.
- Trailing Quiet Zone – Another clear space with no printing following the Stop Character.
Barcode Reader or Barcode Scanner
A barcode reader also called a price scanner or point-of-sale (POS) scanner, is a hand-held or stationary input device used to capture and read information contained in a barcode.
A barcode reader consists of a scanner, a decoder and a cable used to connect the reader with a computer. A barcode reader merely captures and translates the barcode into numbers and/ or letters. And the data must be sent to a computer so that a software application can make sense of the data.
