For each selected characteristic, you can either enter a fixed characteristic value or define a variable.
The function Variable on/off, on the characteristics tab page, lets you enter a variable for the characteristic on which the cursor is positioned. If you choose the flag in the column, a dialog box will appear, in which you can either choose a suitable global variable or create a local variable. The system can recognize internal variables, as the first character in their name is a '$'. If you do not enter this character, the system adds it automatically. For characteristics whose value is to be replaced by a variable, F4 possible entries no longer displays the characteristic values. Instead, it displays the global variables for the characteristic in question.
If you change you mind and no longer want to enter a variable, simply press Variable on/off again. F4 possible entries then display the characteristic values again.