A door entry system is a security feature that controls access to a building or specific area. It typically includes components like a keypad, card reader, or intercom that allow authorized individuals to enter while keeping unauthorized people out. These systems can be used in residential, commercial, and industrial settings. Modern door entry systems often integrate with smart technology, enabling remote access through smartphones or computers. They can also include features like video surveillance and motion sensors, enhancing security and providing real-time monitoring of who enters and exits the premises.