HandHeld Entertainment Quick Check PC600 - Manual (Page 51)

data character: A single numeric digit, alphabetic character or punctuation
mark, or control character, that represents information. Compare to “symbol
character”.
data check character/digit: A digit or character calculated from data and
appended as part of the data string to ensure that the data is correctly composed
and transmitted. Compare to “symbol check character.”
Data Identifier (DI): A specified character, or string of characters, that defines
the intended use of the data element that follows. For the purposes of automatic
data capture technologies, Data Identifier means the alphanumeric identifiers as
defined in ANSI MH10.8.2, formerly known as ANSI/FACT Data Identifiers. (A2)
Reference to be replaced with appropriate ISO/IEC JTC 1/SC 31 reference,
when available.
decode algorithm: The set of rules used to convert the dark and light element
patterns of a machine-readable symbol to data characters.
decodability (V): The measure of the proportion of the theoretical tolerance
derived from the reference decode algorithm, for the element (or distance)
deviating most from its nominal dimension in a scan profile, not consumed by
that element or distance.
decode: The determination of the information encoded in a machine-readable
symbol.
decoder: As part of two-dimensional symbol and bar code reading systems, the
electronic package that receives the signals from the scanner, performs the
algorithm to interpret the signals into meaningful data and provides the interface
to other devices.
delta code: One of two fundamental ways of encoding information in a one-
dimensional medium. An interval, representing one symbol character, is
subdivided into a fixed number of equal-width modules, and values of “1” or “0”
are assigned to each module. Modules with "1s" form the bars while "0s"
correspond to the spaces. A single bar or space may contain many modules.
U.P.C., Code 128, Code 93, Code 49 and PDF417 are delta codes. Compare to
“width codes.”
densitometer: An instrument that measures the degree to which light is
transmitted through or reflected from a material. A calibrated photometer
compares the transmitted or reflective light with the incident light, and the result
may be displayed as percentage reflectance or density.
density (optical): A measure of the relationship between transmitted or
reflected light and the incident light, expressed as the logarithms of their ratio:
Optical density = Log 10 (I/T), where I = Incident light, and T = Transmitted or
reflected light.
43