An intercom, short for "intercommunication system," is a two-way communication electronic device that enables audio and/or video transmission between two or more people. It is a versatile and sophisticated communication tool that can be used in a wide variety of applications, from residential to commercial properties. Intercoms can be used to improve both safety and convenience, and they offer a wide array of features and functions that can be tailored to specific needs and preferences.

Intercoms can be wired or wireless, and they come in a variety of types, including:

• Apartment Intercoms: These systems have a door unit at an entrance door and then each apartment or flat has either one or multiple units that can speak to the door and possibly see the visitor, or the door unit rings a landline or cellular telephone.

• Wireless Intercoms: In applications where wires cannot be run, a wireless system is used. There are a broad spectrum of two-way wireless communication devices that include such devices as handheld radios, outdoor wireless callboxes, as well as traditional desktop devices.

• Video Intercoms: These typically have a unit that has a camera, speaker, and a push button that goes at an entrance door, and an internal monitor unit that can communicate with the entrance unit. Some systems can have multiple video monitors internally.

• Internal Office Intercoms: These enable communication between parties inside an office building, such as employees or coworkers. They allow people in different rooms to easily speak with each other.

• External Office Intercom Systems: These enable communication between people in the office and people outside the office, such as visitors or delivery personnel.

Intercom systems consist of two components: the base station, sometimes called a "master station," and substations. The base station is the main component of an intercom system and is installed at a propertys entryway. Substations are installed at various points throughout the building, such as inside an apartment or office. Intercom systems can be used for many applications, but their primary purpose is to enable communication and property access.