The code depends on where you are. Who it the Authority having Jurisdiction?
May I respectfully suggest that you have both work in case one or the other wont or does not? I just saw a compelling presentation from Kings III communication. Impressive product. Otis now has a interactive voice prompt system, equally as impressive.
Ultimately, the building owner gets to choose between the price of a battery or the price of a negligence cause of action or law suit.
