What year did phone companies ad on off switch to vintage phones.?

I remember in the 1960s on what were called "2500 sets" - basically a desk-top, rotary dial phone - had a ringer "volume" thumbwheel on the bottom of the phone. This moved the bell or clapper away from the two units resulting in a softer or louder ring. If you rolled the thumbwheel enough, the bell and clapper would not touch. The clapper would move resulting in a clicking noise, no bell ringing, because the clapper could not reach the bell - essentially turning the ringer off.

As for "renting the phones" from the phone company... Customers were not allowed to attach non-phone company devices until after the "Carterphone decision", there was no "overpayment".

http://en.wikipedia.org/wiki/Carterfone

After Carterfone... well, that's a whole different historical perspective depending on your frame of reference. It did take a while for some folks to understand that they could buy their equipment rather than continue leasing. A short lived industry full of "consultants" who would review your phone bill and provide a report of savings they found (phones not in service) and they would take a cut of that monthly savings...