For the records, interphones are configured through specific resistors (looks like fuses)
Each appartement has its own number (mine is 7) and then I got a fuse with a 7 written on it.
keep the fuse / fuses from the old device, it must have a number on it and a position on the plate (pick a picture to remember). For me I had one fuse with the number 7 written on it, it was placed on the right of the N pin place.
the right position is for the unit (1 to 9 then) and the left position for the dozen (10and above)
now on your new Biticino you have to find the pin board with the N label and put back your fuses on it, in the same order.
I had to put the fuse number 7 on the right position where the N label was written.