powered, depending on whether the relay is normally open or normally closed). They could also be used as a demultiplexer, so that two input lines could control a number of output devices. One input line steps the switch until the correct device is selected, and the other then powers that device. Many other applications are possible. Such switches were used in a series of Japanese cypher machines during World War 2: CORAL, JADE, PURPLE (the names were American). The British code-breaking machine called Colossus used rotary stepping switches, which was used to break the German Lorenz cipher. References External links Explanation of the way a stepping switch works Switches American inventions Telephone exchanges Telecommunications equipment