128 Function Codes
Code 128, EAN128, GS1-128 have five non-data special control codes, called FUNCTION CODES, and 2 control codes to switch from one 128 set (A, B or C) to another. The switching control codes are used by BarDIMM Pro and BarDIMM Box to force one 128 set. As an example, the string “123456” can be printed with both sets A, B, and C. Inserting a character with ASCII value = 134 at the beginning of the string will force BarDIMM Pro and BarDIMM box to use the set B of code 128.
Those special control codes can only be used with the 128 Autoswitch and the GS1-128/EAN128/UCC128 barcodes.
Note that both BarDIMM Code 128 Autoswitch and GS1-128/EAN-UCC 128 analyze the data and optimize the barcode length by switching automatically between sets A, B and C. GS1-128 (also known as EAN128 and UCC-128) already include the FNC1 code as the first character: you should not send it with the data.
Special control codes are inserted by passing the following special decimal ASCII characters value in the bar code:
| ASCII | CODE |
| 128 | SHIFT |
| 129 | FNC 1 |
| 130 | FNC 2 |
| 131 | FNC 3 |
| 132 | FNC 4 |
| 133 | CODE A |
| 134 | CODE B |
| 135 | CODE C |