CDRH Class 2 | No additional software mechanisms are needed to |
| conform to this limit. Laser operation in this class |
| poses no danger for unintentional direct human |
| exposure. |
Character | A pattern of bars and spaces which either directly |
| represents data or indicates a control function, such as |
| a number, letter, punctuation mark, or |
| communications control contained in a message. |
Character Set | Those characters available for encoding in a |
| particular bar code symbology. |
Check Digit | A digit used to verify a correct symbol decode. The |
| scanner inserts the decoded data into an arithmetic |
| formula and checks that the resulting number |
| matches the encoded check digit. Check digits are |
| required for UPC but are optional for other |
| symbologies. Using check digits decreases the |
| chance of substitution errors when a symbol is |
| decoded. |
Codabar | A discrete |
| consisting of digits 0 to 9 and six additional |
| characters: ( - $ : / , +). |
Code | A set of unambiguous rules specifying the way in |
| which data may be represented as numbers and letters |
| used to represent information. |
Code 128 | A high density symbology which allows the |
| controller to encode all 128 ASCII characters without |
| adding extra symbol elements. |
Code 3 of 9 (Code 39) | A versatile and widely used alphanumeric bar code |
| symbology with a set of 43 character types, including |
| all uppercase letters, numerals from 0 to 9, and 7 |
| special characters |
| name is derived from the fact that 3 of 9 elements |
| representing a character are wide, while the |
| remaining 6 are narrow. |
Code 49 | This symbol is a stack of 2 to 8 rows. Each row |
| encodes row count information plus data characters. |
| For more information, go to the AIM web site or the |
| ANSI web site (see Stacked Symbol (2D Symbols)). |
