Each airline uses different system of chimes. For example, 4 chimes for one airline might mean take-off or landing imminent; for another it might mean an inflight emergency. So, do not be scared when you fly and here 5 or more bells - it may be indicating imminent landing for F/A's.
Here are chimes used for Canadi>n:
1 bell - passenger call, lav call, change in cabin signs, five minute warning prior to landing, crew communication via interphone
2 bells - F/A to contact the flight deck for a message
3 bells - Take-off or landing imminent - take your jump seat
5 bells on the ground - evacuate
5 bells inflight - F/A to report immediately to the flight deck to receive emergency instructions
Does anyone know flight deck/cabin communication systems used by other airlines?