Datamax E-Class Mark II Programmer's Manual page 244

The following example prints an EAN128 bar code:
<STX>L
D11<CR>
1W1I000000025002512345&G10Z2133021AK<CR>
121100000000100Barcode W1I<CR>
E
When scanned this bar code will decode as follows:
[C][FNC1]1234[B]5[F1]10Z[C]213302[B]1AK(81)
W1J: Code 128 (with Auto Subset Switching)
Valid characters: The entire 128 ASCII character set.
Variable length
Valid bar widths: The fourth character of record is the width of the narrow bar in dots.
All other bars are a ratio of the narrow bar (2 times the narrow bar width, 3 times the
narrow bar width, and 4 times the narrow bar width).
This printer supports the Code 128 subsets A, B, and C. If the data begins with at least
four numeric characters the default start code is subset C. If there is a non-numeric in
the first four characters or there are less than four then the default start code is subset
B. Subset switching between B and C is based on the following rules:
1. If in subset C and there are an odd number of numeric digits, subset B will be set
prior to the last digit.
2. If four or more numeric digits appear consecutively while in subset B, the character
code C will be set prior to the digits. If there is an odd number of numerics already in
B, the first numeric will be placed in B with the others in C.
3. When in subset C and a non-numeric occurs, subset B will be inserted prior to the
character.
Note that there is no auto switching from, or to, subset A. Standard switches are still
used. See table below.
Subset A: Includes all of the standard uppercase alphanumeric keyboard characters
plus the control and special characters.
Subset B: Includes all of the standard uppercase alphanumeric keyboard characters
plus the lowercase alphabetic and special characters.
Subset C: Includes the set of 100 digit pairs from 00 through 99 inclusive, as well as
special characters. Code128 Subset C is used for double density encoding of numeric
data.
Special Character Handling: Characters with an ASCII value greater than 95 are
considered special characters. To access these values, a two-character reference table is
232
Appendix G – Bar Code Details
Barcode W1I
Class Series 2 Programmer's Manual