Power door locks
From Wikipedia, the free encyclopedia
Power door locks (aka electric door locks or central locking) allow the driver or front passenger to simultaneously lock or unlock all the doors of an automobile or truck, by pressing a button or flipping a switch.
Power door locks were introduced on the luxury Packard in 1956. Nearly every car model today offers this feature as at least optional equipment.
Early systems locked and unlocked only the car doors. Many cars today also feature systems which can unlock such things as the luggage compartment or fuel filler cap door.
It is also common on modern cars for the locks to activate automatically when the car is put into gear or reaches a certain speed. Automatic unlocking when the car is parked is usually also featured on such systems.
[edit] Remote and handsfree
Today, many cars with power door locks also have a remote keyless system, which allows a person to press a button on a remote control (or, on some Ford cars and trucks, enter a combination on an external keypad) to unlock the car without using a key. This system confirms successful (un-)locking through either a light or a horn signal, and usually offers an option to switch easily between these two variants. Both provide almost the same functionality, though light signals are more discreet while horn signals might create a nuisance in residential neighborhoods and other busy parking areas (e.g. short-term parking lots).
Other cars have a proximity system that is triggered if a keylike transducer (Advanced Key or handsfree) is within a certain distance of the car.
Finally, some other includes garage door opener, integrated.
