A typical access control system provides entry control with egress (exit) being uncontrolled. Sometimes egress control is also required and this can be often achieved using a second card reader and/or keypad at the secure side of the door.
Where exit is not controlled, a device called a request-to-exit device (RTE) is used which is wired to the corresponding input of a door controller. Request-to-exit devices are available in many form factors from a simple push-button to a sophisticated motion detector.
When the button is pushed or the motion detector detects motion at the door, the door controller releases the electric lock and disables any door alarm sensors e.g. door forced-open, for a predefined period.