Printronix LQH-HWTM manual Quiet Zone

Chapter 3 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 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 through 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 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.

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