A method for approximately matching a DTMF input character string with a key word and for vocally outputting information in response to the input character string. A telephone apparatus is provided to transmit a dual tone multi-frequency (DTMF) signal by utilizing a character panel including a plurality...http://www.google.com/patents/US5255310?utm_source=gb-gplus-sharePatent US5255310 - Method of approximately matching an input character string with a key word and vocally outputting data
