The unit incorporates a soft melody musical bell. The bell is located at the reception & one led indicator is provided for each room. Each room has a push to on switch which when pressed triggers the lamp & bell. The lamp glows permanently & bell operates only for 3 to 5 seconds (adjustable) .A reset switch is provided to switch off the light. Since the unit is solid state it has a very long life & can also be operated on battery. The unit is extermely useful in hotels, hospitals & offices. A separate reset switch can also be provided for each room.