When I was a kid in the City of Pittsburgh in the late sixties, we had to let the phone ring one full time before answering it. The reason was that my sister might call. She lived 10 miles up the Ohio River from Downtown Pittsburgh. The phone rates from her house to the city were apparently about the same as calling from Timbuktu, so she would call, let it ring once, and hang up. Then my mom would call her back. If mom wasn't home, when got back we would have to tell her who had called, then add, "...and it rang once." I'm pretty sure that the system continued into the early 70s, after we had moved to a suburb on the other side of the city.

Did anyone else have a system like this? Anyone know how the phone company came up with a rate system like that?