Aztec Barcode FAQ & Tutorial

Index:

• Aztec Barcode Overview
• Size and Accuracy
• Printing and Generation
  • Encoding ASCII Functions
  • Encoding Double Byte, Unicode and Extended ASCII Characters
  • Amount of Data Encoded
  • Aztec Encoding Modes
  • Control Characters
• Verifying Aztec Barcodes

-------- Aztec Products -------- Aztec Font and Encoder .NET Windows Forms Control ActiveX Control ASP Server for IIS Java Class, Applet & Servlet Online Generator 2D Barcode Scanners Barcode Printers

• Reading Aztec Barcodes
• The Aztec Inventor and Royalty License Fees
• If an Aztec barcode scanner or verifier is needed, IDAutomation offers several hand-held barcode imagers and verifiers.

Aztec is a very efficient, two-dimensional (2D) barcode symbology that uses square modules with a unique finder pattern in the middle of the symbol, which helps the barcode scanner determine cell locations to decode the symbol. Characters, numbers, text and bytes of data may be encoded. IDAutomation's implementation of the Aztec symbol is based on the ISO standard version released into the public domain by Honeywell, formerly HHP - Hand Held Products.

Fig. 1. Aztec Barcode Example

Aztec is one of the smallest and most dependable barcode symbologies in use. Compared to other barcode types, Aztec symbols are approximately 30 times smaller than a Code 39 barcode representing the same data. The size difference of popular barcode types is compared in the Barcode Symbology Evaluation and Test Sheet. Aztec symbols are also good to use when sending barcodes over faxed documents because the barcode can withstand many poor resolution and scanning issues.

A quiet zone is not required with Aztec symbols because if the unique finder pattern in the center of the symbol. However, some barcode imagers may have difficulty decoding unless a quiet zone of 1 module is present. The quiet zone should be the same color as the background.

The IDAutomation Aztec Barcode Font and Encoder is a collection of encoders and components that generate Aztec symbols with fonts or graphics. Several types of Aztec encoders are available in the package to support multiple operating systems including Windows, MAC and Linux.

Printed barcode symbols may be easily verified with the Print Quality Assessment test found in the Hand Held Products 2D Barcode Imager. The quality assurance test will grade the symbol and report any possible problems. The report below was generated when scanning the symbol in Fig. 1 with PQA enabled:

>> PQA from Hand Held Products <<
AZTEC CODE: 3 layers (Compact) => 23x23 modules
Data Field: 32 data & 19 checks in GF(256), 0 Erasures & 0 Errors
X roughly = 0.020"
[A] < Core Symbol: 0 errors
[A] < Data Safety Margin = 113%
[A] < Horizontal Print Growth = +11% of X
[A] < Vertical Print Growth = +14% of X

The most common method of reading Aztec barcodes is with a camera-based image reader (aka: barcode imager). Most of the hand-held barcode imagers recommended by IDAutomation perform keyboard emulation and receive power from the USB port so that no external power supply is needed. When a barcode symbol is read using keyboard emulation, the data appears at the cursor as if it had been typed in from the keyboard.

Most barcode imagers have the ability to read Aztec barcodes by default, such as the Symbol, Metrologic and Hand Held Products Barcode Imagers. Many hand-held imagers also read very small barcode symbols, such as the Hand Held Products 2D Imager, which reliably reads the IDAutomation Aztec Barcode Font when printed as small as 3 points, which is an X-dimension of 10 mils.

In many cases, it may be desired to have the scanner trigger a form or action in an application. IDAutomation has documented simple methods of accomplishing this task in the USB Barcode Scanner Application Integration Guide.

Aztec allows ASCII codes to be easily encoded for various functions such as tabs and returns. In all IDAutomation products, the tilde (~) may be used to encode ASCII functions according to the documentation. For example; ~d009 is used to encode a tab and ~d013 encodes a return. In many development environments, Chr or Char may also be used to encode the ASCII value directly. For example, the programming examples below encode "ECC" <tab> 200:

Java: DataToEncode= "ECC" + (char)9 + "200";
Visual Basic: DataToEncode= "ECC" & Chr(9) & "200"

It is possible to scan and encode international and extended characters provided the instructions below are followed:

1. Encode the data using byte encoding.
2. Scan the data via the serial interface option (data bits have to be 8N) on the scanner. Normally, keyboard wedges and USB scanners do not support extended characters above ASCII 128, and only scan characters that are actually on the keyboard. Contact the scanner vendor for more information as some of the scanner's internal settings may need to be changed.

It is recommended to limit the amount of data encoded in each symbol to 800 characters or less if possible. Aztec barcode specifications state that a large amount of characters may be encoded in single Aztec symbol, although many hand-held scanners have a difficult time reading symbols that contain over 800 characters. The size of the symbol will vary depending on the amount of data encoded and mode switching between different types of characters, such as between numbers, upper case, lower case, punctuation and byte data.

Products such as the IDAutomation Aztec Barcode Fonts and the Aztec Barcode Components all support automatic encoding mode. The error correction level encoded in the symbol is specified as a value from 5 to 95. More error correction creates a larger symbol that can withstand more damage. It is not recommended to use error correction over 23 with large amounts of data, because this may overload the symbol capacity. The default setting of 0 performs the automatic and recommended selection, which is usually a value of 23.

IDAutomation Aztec Barcode Fonts, Components and Applications use the tilde character "~" to recognize special characters when "Apply Tilde" or "Process Tilde" is enabled. The following tilde options are available:

• ~dNNN: Represents the ASCII character encoded by the 3 digits NNN. For example, ~d009 represents a tab, ~d013 represents a return and ~d065 represents the character 'A'.
• ~1: Represents the character FNC1. When FNC1 appears in the first position (or in the fifth position of the first symbol of a Structured Append), it indicates that the data conforms to the UCC/EAN Application Identifier standard format.

Honeywell (formerly HHP - Hand Held Products) invented the Aztec symbology and placed it in the public domain, therefore no license or royalty fees are required for use.

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