250
Chapter 7Bar Codes
Data Field
UCC/EAN-128 bar codes require a special character called “Function 1”
(FNC1) to immediately follow the start code. ASCII Emulation automatica lly
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.
Thech aracter set for UCC/EAN-128 is the same as the character set for Code
128. See the Code 128 Character Set (Table 68 on page 231). 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
69 on page 232, 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 70 on page 233. 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 will be formatted with spaces or parentheses denoting particula r 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.
Ther eadable data is oriented along the bar code from start code to stop code.
It may be positioned above or below a bar code.
Modulo-103 Check Digit
A modulo-103 check digit is automatically calculated and inserted i n the bar
code symbol immediately in front of the stop code, in the same manner as the
Code 128 bar code. The check digit verifies accurate scanning. The start
code is included in the check digit algorithm. The modulo-103 c heck digit is
not displayed in the readable data field.
Modulo-10 Data Field Check Digit for SSCC-18and SCC-14
AI 00 (called the Serial Shipping Container Code, or SSCC-18) takes 18
additional numerical data bytes. The last data byte is a mod-10 check digit on
theprec eding seventeen data bytes. Counting the two zeros of the application
identifier, the mod-10 check digit is the twentieth byte in the data field.
AI 01 (called the Shipping Container Code, or SCC-14) takes 14 additional
numerical data bytes. The last data byte is a mod-10 check digit on the
preceding 13 data bytes. Counting the zero and the one of the application
identifier, the mod-10 check digit is the sixteenth byte in the data field.