An automatic telephone recorder includes a computer equipped with a soundsignal handling feature and a digital recording medium such as a disk drive.The sound signal handling feature includes an audio input, an audio output andprogrammable means for selectively effecting digital recording on therecording medium of an audio signal applied to the sound signal handling meansinput. A line transformer is connected between a telephone line pair and thesound signal handling means audio input. The sound signal handling means isprogrammed to periodically test the sound signal handling means audio input todetermine if audio or a predetermined transient signal, indicating that thetelephone line has gone from an on-hook condition to an off-hook condition, ispresent. If the audio or transient signal is present, the sound signalhandling means is programmed to institute recording of any audio signalpresent at the sound signal handling means audio input for as long as suchaudio remains. In one embodiment, a pulse stretcher circuit responds tosensing the presence of the pulse by generating a time-extended signal whichthe sound signal handling means can sample, thus relieving the computer fromthe necessity to continuously sample the transient signal source at arelatively high rate which ties up the central processor resources.
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