Encoding
The * character presented below is not a true encodable character, but is the start and stop symbol for Code 39. The asymmetry of the symbol allows the reader to determine the direction of the barcode being scanned. This code is traditionally mapped to the * character in barcode fonts and will often appear with the human-readable representation alongside the barcode.
These tables outline the Code 39 specification:
| Legend | ||
| Format1 | Format2 | Desc |
| W | B | Wide - Black |
| N | b | Narrow - Black |
| w | W | Wide - White |
| n | w | Narrow - White |
(Note, Format1 and Format2 are just two different ways of describing the same underlying encoding, not two variants of Code 39.)
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| Code Details | |||
| Char nr for checksum | Char | Format1 | Format2 |
| 0 | 0 | NnNwWnWnN | bwbWBwBwb |
| 1 | 1 | WnNwNnNnW | BwbWbwbwB |
| 2 | 2 | NnWwNnNnW | bwBWbwbwB |
| 3 | 3 | WnWwNnNnN | BwBWbwbwb |
| 4 | 4 | NnNwWnNnW | bwbWBwbwB |
| 5 | 5 | WnNwWnNnN | BwbWBwbwb |
| 6 | 6 | NnWwWnNnN | bwBWBwbwb |
| 7 | 7 | NnNwNnWnW | bwbWbwBwB |
| 8 | 8 | WnNwNnWnN | BwbWbwBwb |
| 9 | 9 | NnWwNnWnN | bwBWbwBwb |
| 10 | A | WnNnNwNnW | BwbwbWbwB |
| 11 | B | NnWnNwNnW | bwBwbWbwB |
| 12 | C | WnWnNwNnN | BwBwbWbwb |
| 13 | D | NnNnWwNnW | bwbwBWbwB |
| 14 | E | WnNnWwNnN | BwbwBWbwb |
| 15 | F | NnWnWwNnN | bwBwBWbwb |
| 16 | G | NnNnNwWnW | bwbwbWBwB |
| 17 | H | WnNnNwWnN | BwbwbWBwb |
| 18 | I | NnWnNwWnN | bwBwbWBwb |
| 19 | J | NnNnWwWnN | bwbwBWBwb |
| 20 | K | WnNnNnNwW | BwbwbwbWB |
| 21 | L | NnWnNnNwW | bwBwbwbWB |
| 22 | M | WnWnNnNwN | BwBwbwbWb |
| 23 | N | NnNnWnNwW | bwbwBwbWB |
| 24 | O | WnNnWnNwN | BwbwBwbWb |
| 25 | P | NnWnWnNwN | bwBwBwbWb |
| 26 | Q | NnNnNnWwW | bwbwbwBWB |
| 27 | R | WnNnNnWwN | BwbwbwBWb |
| 28 | S | NnWnNnWwN | bwBwbwBWb |
| 29 | T | NnNnWnWwN | bwbwBwBWb |
| 30 | U | WwNnNnNnW | BWbwbwbwB |
| 31 | V | NwWnNnNnW | bWBwbwbwB |
| 32 | W | WwWnNnNnN | BWBwbwbwb |
| 33 | X | NwNnWnNnW | bWbwBwbwB |
| 34 | Y | WwNnWnNnN | BWbwBwbwb |
| 35 | Z | NwWnWnNnN | bWBwBwbwb |
| 36 | - | NwNnNnWnW | bWbwbwBwB |
| 37 | . | WwNnNnWnN | BWbwbwBwb |
| 38 | (space) | NwWnNnWnN | bWBwbwBwb |
| 39 | $ | NwNwNwNnN | bWbWbWbwb |
| 40 | / | NwNwNnNwN | bWbWbwbWb |
| 41 | + | NwNnNwNwN | bWbwbWbWb |
| 42 | % | NnNwNwNwN | bwbWbWbWb |
| * | NwNnWnWnN | bWbwBwBwb | |
Please Note: In between each character (the start and stop characters included) there is a thin space (shown as w below). For example, if you wanted a Code 39 barcode composed of the letter "A", you would need the following to be encoded (using Format 2 as described above): "*A*". ww
The code will not be read without these spaces. Barcode fonts invariably include this space within the glyph for the character.
Read more about this topic: Code 39