up is made up of the following character groups similar to the arrangement found on a standard 12 key telephone keypad with an u201c _ u201d character indicating unavailability a null value or an alternative character group 1 1 2 3 4 5 6 7 8 9 0 group 2 _ a d g j m p t w _ group 3 _ b e h k n r u x _ group 4 _ c f i l o s v y _ when in alphanumeric mode each of the perimeter regions represents no more than one character from the currently selected character group when a signal to increment the character group that the perimeter regions are representing is received each of the perimeter regions is assigned a character from the succeeding character group specified similarly when a signal to decrement the character group that the perimeter regions are representing is received each of the perimeter regions is assigned a character from the preceding character group specified when the first or the last group is reached the system can be programmed to wrap around to the last or first character groups respectively alternative schemes can also be arranged to customize the character assigned to a region according to the current state of the system an alternative character set which contain the characters u201c q u201d and u201c z u201d can be arranged as follows group 1 1 2 3 4 5 6 7 8 9 0 group 2 _ a d g j m p t w _ group 3 _ b e h k n q u x _ group 4 _ c f i l o r v y _ group 5 _ _ _ _ _ _ s _ z _ the actions.