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UCC/EAN-128
Quiet Zone
Both ends of the bar code structure require blank quiet zones. The quiet
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. You must provide sufficient space on the form for the quiet
zones.
Start/Stop Codes
The start and stop codes identify the leading and trailing ends of the bar code.
UCC/EAN-128 uses unique start codes for character subsets B and C, and a
stop code common to both. An automatic mode switching feature is used to
generate the correct start code based on the first four data field characters.
Data Field
UCC/EAN-128 bar codes require a special character called "Function 1"
(FNC1) to immediately follow the start code. VGL automatically supplies this
character, so it must not be included in the data field by the user.
A character is made up of three bars and three spaces, each varying in width
from 1 through 4 modules, for a total of eleven modules. The number of
modules making up the bars is even. The stop code has four bars and is 13
modules wide.
The character set for UCC/EAN-128 is the same as the character set for Code
128. Refer to the Code 128 Character Set (Table 32). Every character is
interpreted according to the currently active character subset. UCC/EAN-128
uses subset B and subset C only. Subset B, shown in Table 32, includes all
standard alphanumeric keyboard characters, lowercase alphabetical
characters, and special characters. Subset C interprets the characters as
pairs of numbers 00 through 99, along with some special characters, as
shown in Table 32. The start code or subset switch code determines whether
a particular bar code character is decoded as one character or as a pair of
numbers.
Readable Data
The optional printed data field (PDF) provides a human-readable
interpretation of the bar code data. When the printed data field is enabled by
use of the "PDF" parameter, the overall height of the bars is reduced to make
room for a guard band and the human-readable characters. The printed data
field is formatted with spaces or parentheses denoting particular data fields
such as the application identifier. Special characters such as start, stop,
subset switch, modulo-103 check digit, and FNC1 do not appear in the
human-readable data.
Refer to Figure 23. Using Level I syntax ^B (horizontal) or ^C (vertical
clockwise rotation), the readable data appears below the bar code, reading in
the direction of start code towards stop code. Using Level II syntax (^IBARC),
the bar code may be oriented with any of the graphics commands ^M, ^V, ^U,
or ^E; and the human-readable data may be positioned above or below the
bars, still reading in the direction of start code towards stop code.
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