Printronix LQH-HWTM manual Quiet Zone

Chapter 3 Bar Codes

Quiet Zone

Both ends of the bar code structure require blank quiet zones. The quiet zones must be at least 0.25 inches wide and completely blank to ensure accurate reading of the start/stop codes and to prevent adjacent bar codes from overlapping. Be sure to provide sufficient space on the form for the quiet zones.

Start/Stop Codes

The start/stop code is a unique character identifying the leading and trailing end of the bar code. The start/stop code is automatically produced with each bar code. The start/stop code structure permits bidirectional bar code scanning.

Data Field

The bar code symbol uses a series of wide and narrow bars and spaces to represent standard alphanumeric characters. Each character is represented by a different series of bars and spaces, both wide and narrow, but is always 16 units in width (for a wide to narrow ratio of 3). Each character starts with a bar and ends with a space.

Readable Data

The optional readable data field provides a readable interpretation of the bar code data. It can be printed above or below the bar code symbol.

Check Digit

A mandatory modulo-127 check digit is inserted into the bar code to verify accurate scanning.

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