Figure 8-1 Code 128 Subset Switching - Microcom 428LT Operator's Manual

Chapter 8
for the encoding of the full 128 ASCII character set along with special control codes. This
bar code uses automatic compression. The printer will automatically choose the most
efficient subset and insert the appropriate special function code listed in Table 16. It is
possible to force a subset change by inserting the appropriate code while in automatic
compression, however it is not recommended. Please note that if a subset is forced while
using automatic compression the printer will automatically switch to subset C if 6 or more
numeric characters are contained in the data string. Once the even number of characters
has been processed, the printer will then switch to subset B. This could create problems if a
user sent 6 numeric characters while forcing subset A ("#7123456"). The printer would
automatically switch to subset C and then back to subset B resulting in an undesired bar
code due to the extra function codes. If specific control of the subsets is a requirement,
then the manual compression bar code should be used.
Code
#0
#1
#2
#3
#4
#5
#6
#7
#8
#9
##
8.1.15 Code 128 (Manual Compression), TCI 41
The Code 128 bar code is a variable length, high density, alphanumeric symbology that is
extensively used worldwide. This bar code uses three subsets (A, B, and C) which allows
for the encoding of the full 128 ASCII character set along with special control codes. This
bar code uses manual compression, which provides full control by manually shifting
between the available subsets using the special function access codes. The codes (#n) are
placed within the data string to access the desired functions listed in the table below. When
using manual compression the printer defaults to subset B if no start code is defined. The
printer will also not attempt to compress the data unless subset C is used. Once in subset
C the user must send the appropriate code (#n) to return to either subset A or B.
The
printer
defaults to
subset B
428LT Operator's Manual - 880040-0200
SUBSET A
FNC3
FNC2
SHIFT
CODE C
CODE B
FNC4
FNC1
START
N/A
N/A
#
Table 8-3 Code128 Special Function Access
ABC#3012345#5abc
The "#3" code, while in
subset B, switches to
subset C.
Figure 8-1 Code 128 Subset Switching
SUBSET B SUBSET C
FNC3
FNC2
SHIFT
CODE C
FNC4 CODE B
CODE A CODE A
FNC1 FNC1
N/A
START
N/A START
#
The "#5" code, while
in subset C, switches
to subset A.
Bar Codes
N/A
N/A
N/A
N/A
N/A
N/A
N/A
8-7