User's Manual

Chapter 6 — Bar Code Symbologies
CK60 Series Handheld Computer User’s Manual 117
The fundamental requirement called for a symbology capable of being
printed by existing data processing printers (primarily dot-matrix printers)
that produce daily, work-in-progress, job, and product traceability docu-
ments. The ability to print identification messages between 10 and 32 char-
acters long, on existing forms and labels deemed an important requirement.
Code 128 uniquely addresses this need as the most compact, complete,
alphanumeric symbology available.
Additionally, the Code 128 design with geometric features, improves scan-
ner read performance, does self-checking, and provides data message man-
agement function codes.
Code 128 encodes the complete set of 128 ASCII characters without add-
ing extra symbol elements. Code 128 contains a variable-length symbology
and the ability to link one message to another for composite message trans-
mission. Code 128, being a double-density field, provides two numeric val-
ues in a single character.
Code 128 follows the general bar code format of start code, data, check
digit, stop code, and quiet code. An absolute minimum bar or space dimen-
sion of nine mils (0.010 inch minimum nominal ± 0.001 inch tolerance)
must be maintained.
Characters in Code 128 consist of three bars and three spaces so that the
total character set includes three start characters and a stop character.
UCC/EAN-128 Shipping Container Labeling is a versatile tool that can
ease movement of products and information. The Shipping Container
Labeling bar code can take any form and usually has meaning only within
the company or facility where applied.
Because this random data can get mistaken later for an industry standard
code format, the UCC and EAN chose a symbology uniquely identified
from these other bar codes. This standard is for maximum flexibility, to
handle the diversity of distribution in global markets by cost efficiency.
The UCC/EAN-128 Container Labeling specification calls for a FUNC1
to immediately follow the bar code’s start character. FUNC1 also follows
any variable-length application field. The specification also calls for the
computer to send “]C1” for the first FUNC1. The specification requires
that the computer send a “<GS>” (hex 1D) for subsequent FUNC1 codes
in the bar code.
Because “<GS>” is not compatible with computer emulation data streams,
the Uniform Code Council has been asked to change the specification. This
change is made to send the same three character sequence “]C1” to identify
the embedded FUNC1 codes.
This implementation should provide for clean application coding by identi-
fying the same sequences for the same scanned codes. If the communication
of bar code types is enabled, the Shipping Container Label codes precede
with a “J”. These strings will appear on the computer display. The applica-
tion may have to allow for strings longer than 48 characters (maximum