Printronix ThermaLine Series - Manual (Page 203)

5–65 Bar Codes
Quiet Zone
Quiet zones extend on both ends of the bar code to permit the scan to begin
and end in a blank area. The IGP/PGL automatically produces an 11-
module-wide left quiet zone; you are responsible for providing sufficient
space (minimum of seven modules) on the form for the right quiet zone.
The number system character is also printed automatically in the left quiet
zone.
Start/Center/Stop Codes
The start/center/stop codes are special character codes marking those
portions of the bar code. These codes are automatically provided.
Number System Character
The number system character field allows you to provide a code to a class
or type of item. The first character in the data field is used as the number
system character.
Data Field
The bar code symbol uses a series of varying width bars and spaces to
represent a limited character set (numbers 0–9 and Special Characters Start,
Center, and Stop). The bars and spaces vary in width from one to four
modules. Each character consists of two bars and two spaces that total
seven modules. The symbol coding of the left data field is different from
the right data field to permit read direction sensing.
The optional 2– or 5–digit add–on data field is placed within the delimiter
at the end of the bar code data and typically identifies a periodical issue
number or price, respectively.
Readable Data
The human readable data field provides a readable interpretation of the bar
code data. It can either be suppressed or printed below the bar code symbol.
Check Digit
The modulo–10 check digit is automatically calculated and inserted in the
bar code symbol. The check digit verifies accurate scanning. The number
system character is included in the check digit algorithm.