2D Matrix Symbologies; Code One - Intermec 4400 User Manual

4400 Bar Code Label Printer User's Manual
PDF 417
PDF 417 is a stacked 2D symbology that provides the ability to scan across
rows of code. Each row consists of start/stop characters, row identifiers, and
symbol characters (called "codewords"). Each codeword consists of four bars
and four spaces and contain the actual data. In addition to being able to
condense a large amount of information into the stacked format, PDF 417
provides an extensive error detection and correction option. Up to 510
characters can be recovered if they are lost due to an error in scanning or if the
label is damaged. PDF 417 codes can be scanned with a laser scanner or
imaging device that features 2D code scanning capability.

2D Matrix Symbologies

2D matrix symbologies, such as Code One, use both the horizontal and vertical
axes to encode data even more efficiently than stacked symbologies. 2D matrix
codes are created as a matrix of square elements, with each element being
either white or black to encode data in a binary code. Extensive error detection
and correction codes are appended to 2D matrix symbologies, often
automatically.
2D matrix symbologies generally cannot be read with a laser scanner. Instead,
they are read by a digital imager that captures the entire symbol at once instead
of scanning each component individually. Since the components of 2D matrix
symbologies are decoded after the image is captured, they permit very fast
data collection.

Code One

Code One is a 2D matrix symbology that stores data directly in a matrix in a
checkerboard pattern. This matrix makes Code One especially useful for
applications such as small parts labels that do not provide sufficient space for
linear bar codes. Code One automatically generates error correction symbol
characters that are added to the matrix. In addition to data storage and error
correction symbols, each Code One symbol contains a set of horizontal lines in
the center, called a finder pattern, that helps readers quickly locate and identify
each symbol. Code One symbols also contain vertical reference bars to help
readers locate the relative positions of each data bit.
Code One symbols accommodate varying amounts of data using a different
method than other codes. Other codes adjust their size to fit the data exactly.
Code One symbols are divided into versions, with each version being a specific
size. Each version can accommodate an amount of data from one bit to the
maximum amount that will fit into that version. If more data is present than
the version can accommodate, the printer will not print the symbol.
A-10