44
Appendix F
Code 128 Specifications
Code 128 is a very powerful bar code, combining an extensive character set
and variable length with compactness and error checking. The character set
contains all 128 ASCII characters with each character made up of three bars
and three spaces. Each element (bar or space) varies from one to four units in
width, totaling 11 units of width per character. Code 128 contains two levels
of error checking:
•
Each character is checked for internal parity, and
•
The last character is a checksum.
Code 128 has three subsets, A, B and C. Subset A
contains alphanumeric characters and unprintable
control characters, subset B contains alphanumeric
characters plus printable control characters and subset C
contains only numeric characters and uses a 2-character
encoding scheme to create a more compact bar code.
Code 128 uses an internal Mod 103 check character that
is not displayed by the bar code reader. Code 128 bar codes can be made up of
only one subset or may be a combination of several.
The Code 39 features of Accumulate Mode, Caps Lock ON and Caps lock
OFF also apply to Code 128.
UCC-128/ EAN-128
UCC-128/EAN-128 Code is a subset of Code 128 adopted by the UCC and
EAN council’s for use as a shipping label symbology. UCC/EAN-128 bar
codes always start with a Function Code 1 character. In addition, all variable
length fields are terminated by a Function Code 1 character unless they are the
last field in the bar code.
The Wireless Reader outputs the following for the special function codes and
start sequences:
]C1 Start C/Function Code 1
^] (GS) Function Code 1 as a variable string terminator
If UCC/EAN 128 is
enabled, the reader looks for the Start C/Function Code 1
to indicate a UCC/EAN 128 bar code.
The UCC Serial Shipping Container Code specification calls for a 19 digit
UCC/EAN 128 code with an additional Mod 10 Check digit (20 digits in all).
12345
