Data Matrix | This error correcting, |
| symbology is capable of encoding various character |
| sets including strictly numeric data, alphanumeric |
| data and all ISO 646 (ASCII) characters, as well as |
| special character sets. The symbology has both error |
| detection and error correction features. Each Data |
| Matrix symbol consists of data regions, which |
| contain nominally square modules set out in a regular |
| array. A dark module is a binary 1 and a light module |
| is a binary 0. There is no specified minimum or |
| maximum for the X or Y dimension. The data region |
| is surrounded by a finder pattern, a perimeter to the |
| data region that is 1 module wide, which is |
| surrounded by a quiet zone on all four sides of the |
| symbol. Two adjacent sides are solid dark lines used |
| primarily to define physical size, orientation and |
| symbol distortion. The two opposite sides consist of |
| alternating dark and light modules. These are used |
| primarily to define the cell structure but also assist in |
| determining physical size and distortion. |
| There are 2 types of Data Matrix symbologies: ECC |
| 000 - 140 with several available levels of |
| convolutional error correction, and ECC 200, which |
| uses |
| JTC 1/SC 31 purposes, only ECC 200 is |
| recommended. The intellectual property rights |
| associated with Data Matrix have been committed to |
| the public domain. |
Data Structure | The stipulation of the type of information that is |
| included in a bar code, such as its order and format. |
Dead Zone | An area within a scanner's field of view, in which |
| specular reflection may prevent a successful decode. |
Decode | To recognize a bar code symbology (e.g., UPC/EAN) |
| and then analyze the content of the specific bar code |
| scanned. |
Decode Algorithm | A decoding scheme that converts pulse widths into |
| data representation of the letters or numbers encoded |
| within a bar code symbol. |
