IBM 4400 manual Upc-E

Chapter 7 Bar Codes

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.

UPC-E

The UPC-E bar code structure is shown in Figure 23 and described below.

SR, SC	START			STOP
	CODE			CODE
POSITION
	QUIET	DATA	CHECK	QUIET	2- or 5-
	ZONE	FIELD		ZONE
HEIGHT			DIGIT		DIGIT
					ADD-ON
			FIELD
					CODE

N C

NUMBER		OPTIONAL	CHECK
	NUMBER SYSTEM		DIGIT
SYSTEM		READABLE
CHARACTER	CHARACTER FIELD	DATA FIELD	CHARACTER

Figure 23. UPC-E Structure

Quiet Zone

Quiet zones extend on both ends of the bar code to permit the scan to begin and end in a blank area. You must provide sufficient space (minimum of seven modules) on the form for the quiet zones. 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 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 through 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.

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