An intercom is rather like a telephone
– it lets two or more people carry on a conversation over a wired circuit. It shares much of the same technology too. As with a telephone system, there are small intercom systems, with just a handful of “stations”, and there are larger ones with many thousands, in different buildings and even in different countries.
You can find intercom stations for prisons, hospitals, for communication by a road, emergency points or almost any other environment.
So what is the difference between a telephone and an intercom?