A party line -- an early method of eavesdropping . Make a call, talk awhile then don't hang up the phone. The person you were talking with has hung up and now made another call , yet you are still on the line so you can hear the conversation. Back then we did it as a prank, to eavesdrop a conversation was something foreign -- not even occurring to most, and to do it you would have been thought of as very strange and dishonest. Nowadays, people do it for a living , in ways not even dreamt of and are looked up to as a protector by fear porn addicts like sharps.
