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Chapter 7Bar Codes
Data Field
The bar code symbol uses a series of varying width bars and spaces to
represent the entire ASCII character set. Each narrow bar or space is one
element; each wide bar or space is three elements; each character in the data
field has a total of sixteen elements.
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.
Check Digit
The optional modulo-127 check digit can be inserted into the bar code to
verify accurate scanning.
UCC/EAN-128
The UCC/EAN-128 bar code structure is shown in Figure 21 and described
below.
Figure 21. UCC/EAN-128Structure
UCC/EAN-128 uses the same bar code and character set as Code 128.
However, in UCC/EAN-128, the Function 1 character FNC1 immediately
follows the start code. The FNC1 character has been reserved exclusively for
UCC/EAN-128.
The UCC/EAN-128 data structure requires an Application Identifier (AI) at the
beginning of bar code data. Each AI determines the format and length of the
data which follows. See Table 73 for more detail.
DATAFIELD QUIETQUIET START STOP
LOWERGUARD BAND
CODE CODEZONE ZONE
OPTIONALREADABLE DATA FIELD
CHECKDIGIT
OPTIONAL
SR,SC
HEIGHT
POSITION
UPPERGUARD BAND