10. The apparatus of claim 9, wherein characters of said second set are displayed in said second display area in positions which are arranged in a matrix of columns and rows corresponding to said predetermined matrix.
9. The apparatus of claim 1, wherein said first selection means comprises a plurality of operator-controlled keys, at least some of which are arranged in a predetermined matrix of columns and rows, and a first character set selection key that, when actuated, enables said at least some keys to individually select characters of said first set.