Had a mad day today my door bell has broken however we noticed and thought we had it fixed but we hadn't and came up from the basement to find a lady sat in the lounge another guest had let in! She didn't mind and was lovely but I felt awful! Spent the next two hours messing with the bells (if I hear another bell I may loose the plot entirely) Ours work on a radio system so you can take a speaker with you anywhere in the building so you can always hear the bell. When it works its great but it has now decided to no longer ring when in my lounge where I am most often sat and can't see either of the doors. My advice is stick to the old fashioned rings with a cable in between the bell and the push button anything battery operated is fatal. (I am baffled as put in all new batteries and now it doesn't work properly). Also read the instructions as when my dad fished them out it said should be changed about every 18 months and they havn't changed them in 4 years so no wonder they arn't working!