Patent US 3,967,273

The disclosure comprises a method and apparatus for using a pushbutton telephone keyboard in which a signal sequence representing a unique symbol is generated by pushing a first button on which the desired symbol is located, each button being labeled with at most a three by three array of symbols, and pushing a second button, which is indicated by the position of the symbol in the array on the first button. Letters and numbers are arranged corresponding to the arrangement of a standard typewriter keyboard, insuring that anyone familiar with the location of letters and numbers on a typewriter can quickly find the letter on the keyboard.