Stenography machines have at least 22 keys. You can press any combination of them simultaneously, so over 4.19 million. See: http://en.wikipedia.org/wiki/Steno

Stenography machines have at least 22 keys. You can press any combination of them simultaneously, so over 4.19 million. See: http://en.wikipedia.org/wiki/Stenotype http://en.wikipedia.org/wiki/Stenotype