How are you all using the ring pro? What I mean if the customer has his cellphone or tablet in another room or they run out of battery - how can he hear the doorbell? Even if the ring pro has a relay and trigger an internal generic doorbell you still need to find your tablet/phone and switch to the app to view who is at the door. Also can the ring pro open the door (i.e is there a relay?)

I have always been used to video doorbells/intercoms that require a few indoor units (mainly cheap touchscreens) where the indoor units are always available "on the wall" and allow you very easily to view who is at the door and also open the door.

So how can the ring pro substitute this?