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Chapter 6— Two-Dimensional Bar Codes
What is a Two-Dimensional Bar Code?
PDF417
MaxiCode
50
A two-dimensional (2D) bar code is like a portable database. For example,
if a package has a serial number encoded with a linear bar code, you could
scan the serial number, look up the number in a computer system, and
gather the information about that package. If the computer system was
unavailable for any reason, the information you were looking for would
also be unavailable. A 2D bar code, however, can contain several different
fields of information in them; essentially a database attached to a package.
The first 2D bar code was just an extension of a one-dimensional bar code.
The user could stack several Code 39 bar codes on top of another. These
types of codes are called stacked symbology or multi-row codes.
Development of scanners capable of 2D scanning allowed use of more
compact and useful symbologies like PDF417 and MaxiCode.
Intermec PL-series printers have capabilities to print PDF417 and
MaxiCode symbols. If your application requires the use of PDF417 or
MaxiCode symbols, we highly recommend acquiring the universal symbol
specification to assist your programming. The specifications include
suggestions on how to structure your data in the code to make it easier to
use.
Please note that you must load a special application before using PDF417
or MaxiCode on your Intermec PL-Series printer. The standard
application loaded in your printer does not support the ability to print
these bar codes.
The PDF417 bar code is a 2D bar code that can contain a very large
amount of data in a small space. If you look at a PDF417 bar code
carefully, it is actually a stack of smaller bar codes. The number and height
of the stacks are controllable by the user. The bar code can contain the
entire ASCII 255 set of characters and has the capability to use different
encoding schemes and different levels of security to correct errors. The
largest amount of data that can be encoded is 2725 characters.
MaxiCode was originally designed by the United Parcel Service (UPS) to
help them automate package delivery and sort packages coming down a
quick conveyor belt. It consists of a bulls eye to help the imaging system
target the bar code and an array of hexagons to represent the data stored in
the bar code. It can contain a maximum of 93 alphanumeric characters or
138 numeric characters. MaxiCode has two different error correction
modes, seven different storage modes, the capability to use character sets
EasyCoder PL-Series Printer Programmer's Reference Manual
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