Symbol LS3478-ER, Справочное руководство

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Glossary GL-5
Data Matrix This error correcting, 2-dimensional matrix symbology is
capable of encoding various character sets including
strictly numeric data, alphanumeric data and all ISO 646
(ASCII) characters, as well as special character sets. The
symbology has both error detection and error correction
features. Each Data Matrix symbol consists of data regions,
which contain nominally square modules set out in a
regular array. A dark module is a binary 1 and a light module
is a binary 0. There is no specified minimum or maximum for
the X or Y dimension. The data region is surrounded by a
finder pattern, a perimeter to the data region that is 1
module wide, which is surrounded by a quiet zone on all
four sides of the symbol. Two adjacent sides are solid dark
lines used primarily to define physical size, orientation and
symbol distortion. The two opposite sides consist of
alternating dark and light modules. These are used
primarily to define the cell structure but also assist in
determining physical size and distortion.
There are 2 types of Data Matrix symbologies: ECC 000 -
140 with several available levels of convolutional error
correction, and ECC 200, which uses Reed-Solomon error
correction. For ISO/IEC JTC 1/SC 31 purposes, only ECC 200
is recommended. The intellectual property rights
associated with Data Matrix have been committed to the
public domain.
Data Structure The stipulation of the type of information that is included in
a bar code, such as its order and format.
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.
Decode Algorithm A decoding scheme that converts pulse widths into data
representation of the letters or numbers encoded within a
bar code symbol.
Decoder An electronic package that receives the signals from the
scanning function, performs the algorithm to interpret the
signals into meaningful data and provides the interface to
other devices.
Density Describes the relative amount of memory contained in a
radio frequency identification tag (see
Bar Code Density ).
Depth of Field The range between minimum and maximum distances at
which a scanner can read a symbol with a certain minimum
element width.
Diffuse Reflection The component of reflected light that emanates in all
directions from the reflecting surface.
Discrete 2 of 5 A binary bar code symbology representing each character
by a group of five bars, two of which are wide. The location
of wide bars in the group determines which character is
encoded; spaces are insignificant. Only numeric characters
(0 to 9) and START/STOP characters may be encoded.
Discrete Code A bar code or symbol in which the spaces between
characters (intercharacter gaps) are not part of the code.