Bar Code 2 is not as wide as Bar Code 1 because all of its
characters are printed with bar symbols from code C.
Only 6 of Bar Code 1’s characters are printed in code C. The
other character has to be printed in code B. Whenever 128
switches from one character set to another, it adds bar
patterns that tell a scanner to switch character sets. Thes e
extra bar patterns cause wider bar codes.
Bar Code Width
The width of a Code 128 bar cod e is determined this way:
•If there are four or more numbers in a row, an even
number of them print in code C.
•If there are four or more numbers in a row with an odd
quantity (e.g., 7 numbers in a row), one of them prints in
code B.
•All other alphanumeric characte rs are printed in code B.
NOTE: The printer determines which character set to use
based on the data. No extern al control of character
set selection is required.
For a given quantity of data, the widest bar code will be the
one that switches character s et most often. Suppose your
data has 14 characters (8 numeric + 6 alphabetic).
The bar code for data arranged like this:
Bar code 1
Data = 1234ABC5678DEF
is wider than data arrang ed
like this:
Bar code 2
Data = 12345678ABCDEF
9400 Series Programmer’s Manual
B-2