In the US, I recall the ringing sound for the caller being different depending on who you were calling. I understood it to be generate by the remote station, po

In the US, I recall the ringing sound for the caller being different depending on who you were calling. I understood it to be generate by the remote station, powering their ringer via the line. Presumably you could still get different ring counts in such a setup if one side hasn't been connected to the call yet.