Parts of a Bar Code Symbol
Each symbology has its own characteristics. Basic characteristics of bar code
symbologies are:
• The number of element widths.
• Two-width symbologies have only two element widths (wide and
narrow). Codabar, Code 39, and Interleaved 2-of-5 are two-width
symbologies.
• Multiple-width symbologies have more than two element widths
(expressed in multiples of the X dimension, as 1X, 2X, 3X, 4X).
Code 128 and UPC/EAN are four-width symbologies.
• Whether it is “discrete” or “continuous.”
• A “discrete” symbology has bar code characters that begin with a bar
and end with a bar. Codabar, Code 39, and Interleaved 2-of-5 are
discrete symbologies. Discrete symbologies require an additional
space between characters for proper construction. This space is
called the “intercharacter gap” (ICG). Typical ICG value is 1X.
• A “continuous” symbology has bar code characters that begin with a
bar and end with a space (or begin with a space and end with a bar).
Code 128 and UPC/EAN are continuous symbologies.
36