DIRECTIONALLY-MAPPED, KEYED ALPHA-NUMERIC DATA INPUT AND OUTPUT SYSTEM COMPRISING A KEY PAD/ARRAY THAT HAS AT LEAST ONE SET OF RADIAL INDICATOR KEYS AND A SEPARATE NUMERICAL KEY GROUP WITH EACH NUMERICAL KEY HAVING INSCRIBED RADIALLY ON ITS SURFACE ALPHA NOTATIONS, SYMBOLS AND COMMANDS; A MICRO-PROCESSOR; A DTMF GENERATOR; AND A LCD DRIVER WHICH DRIVES A DISPLAY
Electrical and Scientific Apparatus