THE remote control priority key, with rolling security code, operates the dome lamp and rear reading lamps, and engages the door deadlocks when pressed twice. It also operates the central locking for keyless entry through the driver's door only, or unlocks all doors when the button is kept pressed. The head and tail lamps also switch on via the key to show the location of the car at night. The horn chirps if a door is left ajar when remote locking. The engine is disabled to immobilise the vehicle when the key is removed from the ignition. A slip-type steering lock prevents the front wheels turning if the steering wheel is forced. The Calais also has an alarm system, operated via remote control power key, which sounds the vehicle's horn when triggered.