Code 39
225
Code 39
The Code 39 structure is shown in Figure 14 and described below.
Figure 8. Code 39Structure
Quiet Zone
Both ends of the bar code structure require blank quiet zones. The qui et
zones must 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. Be sure to provide sufficient space on the form for the quiet
zones.
Start/Stop Codes
The start/stop code is a unique character identifying the leading and traili ng
end of the bar code. The start/stop code is automatically produced wit h each
bar code. The start/stop code structure permits bidirectional bar code
scanning.
Data Field
The bar code symbol uses a series of varying width bars and spaces to
represent standard alphanumeric characters. Each wide or narrow bar or
space is one element; each character in the data field has nine elements. The
structureis three wide elements (bars or spaces) out of the nine total
elements which compose one character.
Readable Data
The optional readable data field provides a readable interpretation of th e bar
code data. It can be printed above or below the bar code symbol.
DATAFIELD QUIETQUIET START STOP
LOWERGUARD BAND
CODE CODEZONE ZONE
OPTIONALREADABLE DATA FIELD
CHECKDIGIT
OPTIONAL
SR,SC
HEIGHT
POSITION
UPPERGUARD BAND