Printronix ThermaLine Series - Manual (Page 250)

Bar Codes 5–112
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 must provide 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/Stop Codes
The start/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 for all UPC–E and UPC–E0 bar codes
must be zero.
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
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.
For UPC–E, eleven digits are expected, which are compressed down to the
six encoded symbol characters. For UPC–E0, six compressed digits are
expected.
The optional 2– or 5–digit add–on data field is placed at the end of the bar
code 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 above or 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.