IBM 4400 manual Upc-A

UPC-A

The modulo-10 data field check digit for both SSCC-18 and SCC-14 is printed in the bar code as the second half of the last number pair using subset C. It is displayed in the human-readable data field as the twentieth byte for SSCC-18 or the sixteenth byte for SCC-14.

ASCII Emulation automatically calculates the modulo-10 check digit for SSCC-18 if only 17 data digits are provided following the application identifier of 00.

UPC-A

The UPC-A bar code structure is shown in Figure 22 and described below.

SR, SC

POSITION

NUMBER SYSTEM CHARACTER

	START CODE		CENTER CODE	STOP CODE
QUIET	LEFT DATA		RIGHT DATA	QUIET	2- or 5-
ZONE	FIELD		FIELD	ZONE	DIGIT
					ADD-ON
					CODE
N					C
				CHECK DIGIT FIELD	CHECK DIGIT
	NUMBER SYSTEM	OPTIONAL READABLE			CHARACTER
	CHARACTER FIELD		DATA FIELD

HEIGHT

Figure 22. UPC-A 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 are responsible for providing 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/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.

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