I know that the first circuit sends scan signals to the keypad.I have to put some external circuirty. But I don't know what to put there. I didn't meant by

' The bad thing is that I don't have time to figure out how does the Siemens micro process the keypad '
to say that I can't deal with it . I can, but this takes time. I have enough time to do this on that device I have, but I'll have to do this in a place where I will have 30 minutes to capture the keypad and there will be no time for signal measuting . That's why I said I need a quite 'universal' sollution. I can connect over the rows and columns. and I have to process the keypad in parallel with the original processor from the pcb