User's Manual

Bar CodesAppendix —C
364 700 Series Color Mobile Computer User’s Manual
Code 93
The introduction of Code 93 provided a higher density alphanumeric
symbology designed to supplement Code 39. The set of data characters in
Code 93 is identical with that offered with Code 39. Each character con-
sists of nine modules arranged into three bars and three spaces.
Code 93 uses 48 of the 56 possible combinations. One of these characters,
represented by a square, is reserved for a start or stop character, four are
used for control characters, and the remaining 43 data characters coincide
with the Code 39 character set. An additional single module termination
bar after the stop character concludes the final space.
Code 93 is a variable length, continuous code that is not self-checking. Bar
and spaces widths may be one, two, three, or four modules wide. Its struc-
ture uses edge-to-similar-edge decoding. This makes the bar code immune
to uniform ink spread, which allows liberal bar width tolerances.
Code 93 uses two check characters. Its supporters believes this makes it the
highest density alphanumeric bar code. The dual check digit scheme pro-
vides for high data integrity. All substitution errors in a single character are
detected for any message length.
Code 128
Code 128 (C128) is one of the newest symbologies used by the retail and
manufacturing industries. It responds to the need for a compact alphanu-
meric bar code symbol that could encode complex product identification.
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
characters long, on existing forms and labels deemed an important require-
ment.
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 ad-
ding extra symbol elements. Code 128 contains a variable-length symbolo-
gy and the ability to link one message to another for composite message
transmission. Code 128, being a double-density field, provides two numer-
ic values in a single character.
Code 128 follows the general bar code format of start zone, data, check
digit, stop code, and quiet zone. An absolute minimum bar or space di-
mension of nine mils (0.010 inch minimum nominal ± 0.001 inch toler-
ance) must be maintained.
Characters in Code 128 consist of three bars and three spaces so that the
total character set includes three d ifferent start characters and a stop char-
acter.