... ,Home,KTV,etc 3.Match switch to use,display Room NO.doorbell,D.N.D and so on Door chime switchThere are two ... is 10V.2.Heavy current(High voltage220V) door chime:Don't need to use together with whole system,and can use ... ,because its input voltage is 220V.Function and Feature:1. Display room,Do not disturb ,Make up room,Please wait a ...