I admit, normally, I extensively search before I post. But wasn't
sure how to "explain" this issue.

Wife's VERY old aunt is still pretty mobile. But she likes to work in
the backyard of her suburban tract home on nice days.

She's a sociable sort and actually has a fair number of visitors
during the week. If she is gardening in the backyard, people ring the
bell and she doesn't hear it.

My solution was to leave door unlocked so friends could come through.
Other relatives are agast at my solution. So, solution 2 is to have
some sort of set-up so if someone rings front door bell, it rings loud
in the back.

I figure some of you experts would know how to do this and could
explain it to that even a electrical nimcompoop such as myself could
follow your direction.

Any brave souls?