I have a ring but no fingers
Notifications of trouble I can tell, before the waters start to swell
A problem you see, can be alerted by me
When all is given to atone, I am not a telephone
Several rings do not make me. I am not a tree
Never see me on a farm, just no cause for that kind of alarm
Guess away you may
My sound is clear as the night, never expecting fervent slight
My purpose in life, is to reduce your strife
What am I ?