Printronix LQH-HWTM manual Quiet Zone

Chapter 3 Bar Codes

Quiet Zone

Both ends of the bar code structure have 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. You must provide sufficient space on the form for the quiet zones.

Start/Stop Codes

Unique start and stop codes permit bidirectional scanning. Both start and stop codes contain bars and spaces. They are automatically produced.

Data Field

The bar code symbol uses a series of wide and narrow bars and spaces to represent numeric characters. The structure is 2 wide elements (bars or spaces) and 3 narrow elements. In the bar code, two characters are interleaved (paired); bars are used to represent the first character in the pair and spaces are used to represent the second character in the pair.

German I-2/5 and ITF-14 are special cases of Interleaved 2/5 bar codes. While Interleaved 2/5 has a variable data field, German I-2/5 is restricted to 11 or 13 digits, and ITF-14 is restricted to 13 digits.

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

The modulo-10 check digit can be inserted into the bar code to verify accurate scanning.

Interleaved 2/5 can be printed with or without a check digit, but German I-2/5 and ITF-14 have the check digit automatically included.

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