User's Manual

Bar Code SymbologiesAppendix —B
418 700 Series Color Mobile Computer User’s Manual
Codabar
Codabar was for retail price-labeling systems. Today it is widely accepted
by libraries, medical industries, and photo finishing services.
Codabar is a discr ete, self-checking code with each character represented
by a stand-alone group of four bars and three intervening spaces.
Four different start or stop characters get defined and designated “a”, “b”,
“c”, and “d”. These start and stop characters are constructed using one
wide bar and two wide spaces. A complete Codabar symbol begins with
one of the start or stop characters followed by some number of data char-
acters and ending in one of the start or stop characters.
Any of the star t or stop characters may be used on either end of the sym-
bol. It is possible to use the 16 unique start or stop combinations to identi-
fy label type or other information.
Since Codabar is variable-length, discrete, and self-checking, it is a versa-
tile symbology. The width of space between characters is not critical and
may vary significantly within the same symbol. The character set consists
of “0” through “9”, “-”, “$”, “:”, “/”, “.”, and “+”.
The specific dimensions for bars and spaces in Codabar optimize perfor-
mance of certain early printing and reading equipment. Codabar has 18
different dimensions for bar and space widths. So many different dimen-
sions often result in labels printed out of specification and cause Codabar
printing equipment to be more expensive.
Code 11
Code 11 satisfies the requirements for a very high density, discrete numer-
ic bar code. The name Code 11 derives from 11 different data characters
that can be represented, in addition to a start or stop character.
The character set includes the 10 digits and the dash symbol. Each charac-
ter is represented by a stand-alone group of three bars and two intervening
spaces. Although Code 11 is discrete, it is not self-checking. A single print-
ing defect can transpose one character into another valid character. One or
two check digits obtain data security.
The specifications f or Code 11 suggest that this code should have a narrow
element width of 7.5 mils. This results in an information density of 15
characters per inch.
Code 39
Code 39 (C39) is the most widely used symbology among the industrial
bar codes. Most major companies, trade associations, and the federal gov-
ernment find this code to f it their needs. The main feature of this symbol-
ogy is the ability to encode messages using the full alphanumeric character
set, seven special characters, and ASCII characters.
Programming for this symbology can be for any length that the application
requires. The application program for the 751G Computer handles
symbology at least one character but no more than 32 characters in length.