Our facility it seems its in ancient times, we have no idea where a nurse is, you must hunt them down with your own either sense or instinct. Some nurses just give up and hollar your name down the hall. That or people do Marco Polo ^.^;; This is the public system though, government wouldn't spend that much money for ease of location I guess.
I've worked in some private systems and they had a button you pressed on entering the room, so a green light shows up outside the door. So that was much easier. Intercom is never used in any system I've worked in. Phones are often used in aged care that I remember.