The scandal came to light after the discovery of a wire-tap recording, made without judicial approval, of a conversation between South Korea's ambassador to the United States and a top executive from the Samsung Group.

ECONOMIST: The past returns to haunt South Korea's secret services

Note that an American, Oberlin Smith, described how magnetic recording could be done on magnetic impregnated thread or steel wire in 1888.

FORBES: Magnetic Tape Turns 60