The history of the Electromatic goes back to 1924, when the North East Electric Company received patent rights for the power roller from James Smathers.
In the 1950s, modified standard versions of the A, B, and C models were used as console typewriters or terminals on many early computers (e.g., JOHNNIAC, IBM 1620, PDP-1).
The Executive model differed in having a multiple escapement mechanism and four widths for characters, allowing it to simulate 12 point 'ragged right' typesetting.
The proportionally spaced typewriter immediately leaped to the apex of the world bureaucracy and administrative culture when President Roosevelt was presented with the first machine off the line.
The Armistice documents that ended World War Two were typed on an IBM, as was the original United Nations Charter.
With proportional spacing, the IBM Executive typewriters could abandon the wide serifs and use fonts that closely resembled those used in typesetting.
This change also allowed IBM greater flexibility in font design, as the lowercase "l" and uppercase "o" did not have to be usable as the corresponding digits.
Having introduced them on the Executive, IBM maintained the separate digit keys on later non-proportional-spacing typewriter models, including the Selectric series.