Intercom systems are used in many buildings across New York City. Basically, this is an inter-communication implement that allows people to talk to each other without having to rely on cell phone signals. A microphone is embedded in the main gate, and anybody who arrives on the doorstep can press the button to initiate a call. Once you pick up the receiver (located inside), you can talk to the person standing outside without even opening the door. These systems clearly offer a number of different advantages to homeowners.