H-1
Appendix H
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, a Function Code 1 character terminates all variable length
fields unless they are the last field in the bar code.
The RF Terminal 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). The Mod 10 Check digit is calculated the same as the
Interleaved 2 of 5
example in
Appendix D
. It is the data length as well
as the MOD 10 check digit that distinguishes the
UCC
Serial Shipping
Container Code
from other UCC /EAN 128 bar codes.
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