What is Symbology?
Symbologies are the schemas how the data is encoded into physicals bars
and spaces. Symbology is analogous to the language. The reading and
printing equipments must use the same language to communicate with each
other, this language is called symbology.
Generally speaking, symbologies can be divided into two major
categories: width-modulated and height-modulated. Except these used in
postal applications, most symbologies encode the data into the different
width of the bars. All the bars have the same height. The contrary holds
true for height-modulated symbologies: all bars have the same width, and
the data is encoded into different length of the bars.
We call the data to encoded “message” or “code”. When we talk about the
physical representation of the message, we refer as “symbol” or “barcode”
in this web site.
Symbology Configurations
The symbology configuration refers to the shape of a symbol. There are
three major configurations: linear, 2D stacked and 2D matrix. The linear
symbology is most widely used, consisting only one row of bars and spaces.
The 2D stacked symbol uses multiple rows of bars and spaces. Each row in a
2D stacked symbol has the same height. 2D matrix symbol uses both width and
height to encode the data.
Character Set
The character set defines what kind of data the symbology encodes.
Generally there are three types of character sets: numeric, alpha-numeric
and full ASCII. Some symbologies can encode arbitrary binary data. Not all
alpha-numeric symbologies share the same character set. Most alpha-numeric
symbologies can only encode several characters in addition to letters and
numbers.
Discrete/Continuous
In a discrete symbology, each character ends with a bar and an
inter-character gap separates two adjacent characters. Each character is
treated separately, no end characters are required for scanning.
In ad continuous symbology, there is no inter-character gap and each
character terminates at the starting bar of the next character. Hence, a
stop character is usually needed. Continuous symbologies usually encode
more information than the discrete symbologies.
|
