On Tue, 13 Oct 2020 14:54:51 +0100, T i m wrote:

Some elderly relies had a wind-up clockwork one on the back of the
front door and that was pretty effective and you were in no doubt that
it's worked as the whole door resonated it in both directions!

Oh, yes my Grandad had one of those, excellent door bell. You can
still get them, going rate seems to be just over £30.00

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Cheers
Dave.