terry wrote:
2) there was a British system IIRC named "Rhythmatic" (sounds like an
exercise class doesn't it?) which sent pulses of a certain frequency
down the power lines which caused a mechanically tuned relay to swing
back and forth until it's contacts would switch things such as street
lights on or off, remotely.

Both the name, "Rhythmatic," and your description sound like a sex
technique.

Where can I get more information?