以下是英文解說:
In the A320 family the "NO SMOKING" (optionally "NO PORTABLE ELEC DEVICE" on newer frames) switch controls the emergency cabin lights like so:
ON: Emergency cabin lights are always on and the ECAM (upper central display) message "NO SMOKING" or "NO PED" appears
AUTO: As above but only when the gear is down and locked. The lights and ECAM message should appear as the gear locks down (3 greens) and as it unlocks to raise (at least 1 red).
OFF: The emergency cabin lights remain off and no ECAM message.
Any change in state of the emergency lights is accompanied by a chime in the cabin. The Fenix does get this one wrong as the chime sounds as the gear finishes lifting whereas it should chime as soon as the gear unlocks to lift (basically when you select gear up).
EDIT: For clarity the seatbelt switch optionally has an AUTO position but very few airlines use it.