Phone Systems are often thought of as a tool for businesses, enabling the use of mutiple extensions, call transfers, etc., but they can also be useful in larger homes. Phone Systems are often installed for there ability to be used as an intercom systems. You can page directly from room to room, or you can page all phones in the house at once. You can also use them to talk to a "door station" located at the front door, allowing you to know who is at the door before you get there, or you could let them know that you will be at the door soon to let them in. Although the intercom features are the main reason people install phone systems into homes, they still have all the other features you generally associate with business: multiple lines, multiple extensions, call transfers, etc.