IBM 4400 manual Msi

MSI

MSI

The MSI bar code structure is shown in Figure 17 and described below.

			OPTIONAL
			CHECK DIGIT
SR, SC
POSITION
		UPPER GUARD BAND
QUIET	START	DATA FIELD	STOP	QUIET
ZONE	CODE		CODE	ZONE

HEIGHT

LOWER GUARD BAND

OPTIONAL READABLE DATA FIELD

Figure 17. MSI Structure

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. You must provide sufficient space on the form for the quiet zones.

Start/Stop Code

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 each numeric character. The structure is four wide elements (bars or spaces) and four narrow elements. Each character contains four data bits, with each 0-bit made up of a narrow bar/wide space arrangement and each 1- bit made up of a wide bar/narrow space arrangement.

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

If specified, the modulo-10 or modulo-11 (or both) check digit is automatically calculated and inserted in the bar code symbol. The check digit verifies accurate scanning.

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