I lived in Illinois Bell territory in the 80's and our ringbacks were 571 and then the last 4 digits of your number, but that was only for our prefix. Other prefixes had a different 3 digits to dial, like 574, 576, 579. You hung up, picked up, then hung up again and it would ring forever. It was a free call from pay phones too, so I would always make pay phones ring.
In the 90's, a small town I lived in (GTE was the phone company) all you had to do to make your own phone ring was dial your own phone number and then hang up. I don't think I ever tried it from a pay phone there though.
Welcome to PLA. I look forward to meeting you when you reach the 11th inner ring.