Barcode Basics
 The Barcode Structure
Quiet zone (margin)
The right and left ends of the bar code symbol. If the margin is not wide enough, the bar code reader cannot scan the bar code data.
Both the right and left margins should be at least 10 times as wide as the narrow width (minimum element width).
Start/stop character
Character to indicate start or end of the data.
Start/stop character varies depending on the type of the bar code. CODE 39 uses "*" and CODABAR uses "a", "b", "c" and "d". (EAN and ITF use a bar pattern which indicates the start/end of the data.)
Data (message)
Bar patterns of character (numeral, alphabet, etc.) representing the data are arranged from left.
Check digit
A numeric value calculated to check for read error. It is appended directly after the bar code data.
Bar code length
Bar code length defines the length including the right and left quiet zones. Unless bar code including quiet zones fits in the scan width, the bar code reader cannot scan the data.
Bar code height
It is recommended to make the bar code as high as the printer permits. If the bar code is not high enough, the laser may deviate from the bar code, causing unstable readings. The height is recommended to keep to more than 15 % of the bar code length.
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