Terminology

Quiet Zone

Quiet zone is the blank margin on the either side of a barcode that's used to tell the barcode scanner where a barcode's symbol starts and stops. The purpose of a Quiet Zone is to prevent the scanner from picking up information that does not pertain to the barcode scanned. (The blank margin will not send a scanning signal hence it named "quiet".) As a rule, the Quiet Zone should be ten times the dimension of the narrowest element in the barcode (X dimension) or 1/4 inch, whichever is greater. An undersized Quiet Zone may render a barcode unreadable or readable only from one direction.
barcode quiet zone