Encoding of the Code 93 barcode involves several key steps and rules to generate the barcode symbol from alphanumeric characters. This detailed process ensures that the barcode is correctly encoded and can be accurately decoded by a scanner. Let's delve into the encoding principles of Code 93: |
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1. Character Set |
Code 93 can encode the following characters: |
Uppercase letters (A-Z) Numeric digits (0-9) Special characters: - (dash), $ (dollar), % (percent), . (dot), / (slash), + (plus) |
2. Start/Stop Characters |
Code 93 includes special start and stop characters to indicate the beginning and end of the barcode. These characters are necessary for the barcode scanner to identify where the barcode begins and ends. The start and stop characters in Code 93 are represented by asterisks (*) and can also appear within the encoded data. |
3. Check Characters |
Code 93 uses two check characters (C and K) to provide error detection capabilities. These check characters help verify the accuracy of the barcode during scanning. They are calculated based on the weighted sum of all characters in the barcode, using specific encoding values. |
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4. Character Mapping |
Each character in Code 93 is mapped to a specific pattern of bars and spaces. This mapping defines how each alphanumeric character is represented in the barcode symbol. The mapping ensures that the barcode scanner can interpret the correct data from the barcode. |
5. Encoding Rules |
The encoding of Code 93 follows specific rules: |
Each character is represented by a series of nine modules (bars and spaces). Each module is either narrow (one unit wide) or wide (two units wide). Each character is composed of three bars and three spaces. Each character's encoding includes a start/stop pattern, character encodings, and check characters. |
6. Start Character Encoding |
The start character (*) in Code 93 initiates the barcode and signals the start of a new barcode symbol. Its encoding pattern is unique and differs from standard character encoding patterns. |
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7. Character Conversion |
Characters to be encoded in Code 93 are converted into the corresponding barcode patterns using tables that define the sequence of bars and spaces for each character. For example: |
The character 'A' might be represented by the pattern 101011110. The character '1' might be represented by the pattern 101110010. |
8. Check Character Calculation |
After encoding the data characters (including start and stop characters), the check characters C and K are calculated based on a weighted sum formula: |
C = (sum of values of characters * 1) % 47 K = (sum of values of characters * 2) % 47 |
Where each character has a numeric value assigned according to its position in the character set. |
9. Stop Character Encoding |
The stop character (*) indicates the end of the barcode symbol. Its encoding pattern is similar to the start character but is visually distinct to avoid confusion with data characters. |
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Example Encoding Process |
Let's encode the alphanumeric string 'CODE93': |
1.Data Characters: 'CODE93' C = 12 (value of 'C') + 15 (value of 'O') + 4 (value of 'D') + 5 (value of 'E') + 9 (value of '9') + 3 (value of '3') = 48 |
2.Check Characters Calculation: C = (48 * 1) % 47 = 1 K = (48 * 2) % 47 = 2 |
3.Encoding Sequence: Start Character: * Data Characters: C, O, D, E, 9, 3 Check Characters: C = 1, K = 2 Stop Character: * |
4.Character Encoding: Convert each character and its corresponding check characters into barcode patterns using predefined encoding tables. |
5.Final Barcode Symbol: Combine the start character, encoded data characters, check characters, and stop character to form the complete Code 93 barcode symbol. |
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Conclusion |
Encoding of the Code 93 barcode involves converting alphanumeric data into a specific pattern of bars and spaces using start, data, check, and stop characters. Each character has a unique encoding sequence defined by encoding rules and tables, ensuring accurate and reliable data representation in the barcode symbol. The inclusion of check characters enhances error detection capabilities, crucial for reliable barcode scanning in various applications. |
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