An interesting thing to think about in elevators is who exactly the elevator phone calls, as well. In large buildings it sometimes rings a location staffed 24/7

An interesting thing to think about in elevators is who exactly the elevator phone calls, as well. In large buildings it sometimes rings a location staffed 24/7, like a security desk. In most buildings, though, for better reliability the phone actually rings a dedicated outside answering service for elevator phones. Sometimes this is provided by the manufacturer of the elevator as part of an "all-inclusive" service package, and sometimes they're hired by the property manager, but in a lot of cases the elevator company that does the maintenance programs the elevator phones to call their contracted answering service so as to ensure that they'll be the ones sent out to do the repairs. It's a bit like the plumber leaving you a fridge magnet with their 24/7 line.