Keyboard for entry of text to mobile telephones or personal digital assistants, displays character sets on screen with key selecting character set then character from that set

摘要

The keyboard has a processor which operates in alphabetic modes despite having fewer keys (7) than characters in the alphabet. The keyboard allows access to up to N2 characters from a keyboard with N keys. A key selects a set of characters displayed on the screen, and a second press selects a character from that set. Any one of the N2 characters can be selected with only two key activations.