A door phone, also known as an intercom system, is a communication device designed to manage and monitor access at entry points of residential, commercial, and industrial properties. It allows occupants inside a building to communicate with visitors outside before granting or denying access, significantly enhancing both convenience and security. Over time, door phones have evolved from simple audio-based systems to sophisticated video-enabled solutions integrated with smart technologies.
At its core, a basic door phone system consists of an outdoor unit and an indoor unit. The outdoor unit, typically installed near the entrance gate or door, includes a microphone, speaker, and a call button. When a visitor presses the button, the indoor unit alerts the occupant, enabling two-way communication. This simple setup provides a fundamental layer of security by allowing residents to verify visitors without physically opening the door.