Adapter for use in telephone recording

Abstract

An adapter for use in telephone recording of picking-up electric voice signals from a telephone set and outputting them to a sound recording apparatus, comprising a photocoupler having a light emission device that converts electric voice signals picked-up from the telephone set into optical signals and a photoreceiving device for converting the optical signals again into the electric voice signals and outputting them to the sound recording apparatus incorporated into a package case, whereby the telephone set and the recording apparatus are electrically isolated from each other to prevent intrusion of noises from the recording apparatus to the telephone circuit and eliminate the worry of giving unpleasant feeling to the calling party or the worry that the calling party may suspect the contents of telephone call are under recording.

Dependencies are inferred from the claim text.