Y-40C nurse call light signal -can hold cards showing patient information

waiter call button table call button used for restaurant, hotel, hospital, etc. 

call button for elderly used in nursing homes, beadhouse, hospital, nurse station, healthcare

city security intercom used in atm subway train station airport bank

Y-O-C: one CALL key; Y-Cancel (cancel stick) widely used for restaurant, cafe, bar, drink service.