5525B/31/32 Line Matrix Printer Code V Programmer's Reference Manual

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Chapter 3 Bar Codes
Code 39
The Code 39 structure is shown in Figure 9 and described on the following
pages.
Figure 9. Code 39 Structure
Quiet Zone
Both ends of the bar code structure require blank quiet zones. The quiet
zones should be at least 0.25 inches wide and completely blank to ensure
accurate reading of the start/stop codes and to prevent adjacent bar codes
from overlapping. You are responsible for providing sufficient space on the
form for the quiet zones.
Start/Stop Codes
The start/stop code is a unique character identifying the leading and trailing
end of the bar code. The start/stop code is automatically produced with each
bar code. The start/stop code structure permits bidirectional bar code
scanning.
Data Field
The bar code symbol uses a series of wide and narrow bars and spaces to
represent standard alphanumeric characters. Each wide or narrow bar or
space is 1 element; each character in the data field has 9 elements. The
structure is 3 wide elements (bars or spaces) out of the 9 total elements that
compose one character.
DATA FIELD
QUIETQUIET
START
STOP
LOWER GUARD BAND
CODE
CODEZONE ZONE
OPTIONAL READABLE DATA FIELD
CHECK DIGIT
OPTIONAL
HEIGHT
STARTING
POSITION
DATA
FIELD
QUIET
ZONE
QUIET
ZONE
START
CODE
STOP
CODE
OPTIONAL
READABLE
DATA
FIELD
CHECK
OPTIONAL
HEIGHT
STARTING
POSITION
DIGIT
GUARD
BAND
LOWER