The following problem: I bought a motor home from someone who had the smart solar 75/15 charge controller installed. I would now like to set up the app on my mobile phone (iphone), but I can simply not enter any letters on the display that is to be used to enter the pin or puk, only numbers! But I have to enter letters both when I want to enter the Puk or when I want to enter the password of the previous owner (the previous owner gave me his password). It is to despair. Can anyone give me a hint? (Gladly also in German.)