This looked very interesting, more info and photos here.
Users of the device control where the notes and characters fall on the page with the help of the curved meter on the left that Keaton called the Scale Shift Handle and Scale Shift Indicator. By moving the handle up or down a notch, they tell the typewriter how much to adjust, printing 1/24 of an inch in either direction. Moving one notch up or down will cause the character to fall one musical step either way.
