When I was in highschool I lived in a rural town of about 7000 people that had an analog telephone exchange. I read about the bandwidth limitations, and a frie

When I was in highschool I lived in a rural town of about 7000 people that had an analog telephone exchange. I read about the bandwidth limitations, and a friend of mine and I decided to test them over a local and long distance call. The long distance one cut out pretty much exactly at the frequency the spec said it should, but the local one could transmit and receive much higher frequencies, presumably because it had its own circuit and wasn't multiplexed with other ones. (That led to a lot of unrealized fantasies about creating a homemade super modem for local connections.)