User`s manual

A–21Bar Codes
Data Field
Code 128 bar codes support a full ASCII character set: Subset A provides
standard alphanumeric keyboard characters, control and special characters;
subset B includes all standard alphanumeric keyboard characters, lowercase
alphabetical characters, and special characters; subset C provides 100 digit
pairs, from 00 to 99 inclusive, plus special characters. Table A–3 lists the full
Code 128 character set. The “greater than” symbol (>), followed by one of
various characters, allows you to manually shift between subsets, specify a
particular subset to start with, or to include several non–printable control
characters in the data set. (To include the “greater than” symbol itself, you
must use >0.) This is described in the Mode Selection section below. The
bars and spaces in the printed Code 128 bar code vary in width from 1 to 4
modules. Each character consists of 3 bars and 3 spaces that total 11
modules.
Readable Data
The optional readable data field provides a readable interpretation of the bar
code data. Bar code data is printed below the horizontal bar code. The lower
guard band is provided when the readable data field is selected. The readable
data field is available only in the automatic mode. For 128–UCC, the
optional readable data is broken up by spaces to denote 128–UCC data fields.
Check Digit
For Code 128, the modulo–103 check digit is automatically calculated and
inserted in the bar code symbol. The check digit verifies accurate scanning.
The start code is included in the modulo–103 check digit algorithm.
For 128–UCC, the modulo–10 and 103 check digits are automatically
calculated and inserted in the bar code symbol. The check digit verifies
accurate scanning.
Code 128 Mode Selection
The printer generates Code 128 bar codes in one of two modes: automatic or
manual.