An intercom is a communication device that allows people to talk to each other over short distances, often within a building. It typically consists of a microphone and speaker, enabling two-way communication. Intercoms are commonly used in homes, offices, and schools to facilitate easy communication without needing to move from one location to another. There are various types of intercom systems, including wired and wireless models. Some modern intercoms can connect to smartphones or home automation systems, allowing users to communicate remotely. They are useful for security purposes, as they can be installed at entrances to screen visitors before granting access.