I need to put a "back-tab" into a bar code. I'm assuming I cannot do this, since there is no ASCII equivalent character associated with it, unlike "tab" with is ascii character 0x09
I have a form that I want to fill in by scanning a QR barcode. There is a field on the form that when using the keyboard to fill in - you would select "shift-tab" on your keyboard to go back to the field, and then tab to move onto the next field.
Any idea how I can accomplish this?
Yes there's no "back tab" character.
You can certainly encode byte value 9 in a QR code, and it is entirely valid in QR code byte mode, where bytes are interpreted as ISO-8859-1.
However it's up to the reader as to what's done with the data. Even if there were such a character, it would not necessarily do something specific like enter a form field and be interpreted as a control rather than text.
So no you can't do this, but you could read a QR code and then write custom code to do whatever you need to do based on its content.