Telephone having an audio response function

摘要

A microphone system is provided for picking up ambient sounds including noises and for producing a sound voltage signal. A threshold is obtained from the sound voltage signal for determining a response voice spoken by an addressee in response to the bell tone. A response sound voltage based on the response voice is compared with the threshold, and a response voice signal is produced when the comparison is established. In response to the response voice signal, a line of the telephone is closed.