Abstract: An alphanumeric data input system, and related method, comprising a 3×4 alphanumeric keypad of keys, a display, and a program controlling the operation of these components. The keys represent digits from “0” to “9” and “*” and “#” signs respectively and the keys for digits from “2” to “9” also represent the letters of alphabet sequentially in respective groups of three to four letters. At least one of the keys upon pressing will cause the display to display the letters of the associated group in both lowercase and uppercase and the associated number together in the form of a grid of locations corresponding in position to the keys of the keypad. Subsequent pressing of one of the keys corresponding to the location at which a desired character is displayed will result in input of that character.