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-
12345 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
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.
