Glossary - 3
CDRH Class 2. No additional software mechanisms are needed to conform to this limit. Laser operation in this
class poses no danger for unintentional direct human exposure.
Character. A pattern of bars and spaces which either directly represents data or indicates a control function,
such as a number, letter, punctuation mark, or communications control contained in a message.
Character Set. Those characters available for encoding in a particular bar code symbology.
Check Digit. A digit used to verify a correct symbol decode. The scanner inserts the decoded data into an
arithmetic formula and checks that the resulting number matches the encoded check digit. Check digits are
required for UPC but are optional for other symbologies. Using check digits decreases the chance of
substitution errors when a symbol is decoded.
Codabar. A discrete self-checking code with a character set consisting of digits 0 to 9 and six additional
characters: ( - $ : / , +).
Code 128. A high density symbology which allows the controller to encode all 128 ASCII characters without
adding extra symbol elements.
Code 3 of 9 (Code 39). A versatile and widely used alphanumeric bar code symbology with a set of 43
character types, including all uppercase letters, numerals from 0 to 9 and 7 special characters (- . / + % $and
space). The code name is derived from the fact that 3 of 9 elements representing a character are wide, while
the remaining 6 are narrow.
Code 93. An industrial symbology compatible with Code 39 but offering a full character ASCII set and a higher
coding density than Code 39.
Code Length. Number of data characters in a bar code between the start and stop characters, not including
those characters.
Cold Boot. A cold boot restarts the mobile computer and erases all user stored records and entries.
COM port. Communication port; ports are identified by number, e.g., COM1, COM2.
Continuous Code. A bar code or symbol in which all spaces within the symbol are parts of characters. There
are no intercharacter gaps in a continuous code. The absence of gaps allows for greater information density.
Cradle. A cradle is used for charging the mobile computer battery and for communicating with a host computer,
and provides a storage place for the mobile computer when not in use.
DDCP. See Device Configuration Package.
Dead Zone. An area within a scanner's field of view, in which specular reflection may prevent a successful
decode.
Decode. To recognize a bar code symbology (e.g., UPC/EAN) and then analyze the content of the specific bar
code scanned.