| 摘要 |
APPARATUS FOR OPTICALLY COUPLING A TERMINAL UNIT TO THE PUBLIC TELEPHONE NETWORK THROUGH A PAY TELEPHONE INSTRUMENT AND THE LIKE Apparatus including a terminal unit is optically coupled to a station unit associated with a coin operated type pay telephone instrument permitting a user to access and be connected to the public telephone network via the terminal unit wherein electrical supervisory and audio baseband frequency signals are converted to an infrared energy beam for transmission to the station unit. The station unit senses the infrared energy beam and reconverts it to an electrical supervisory and audio baseband frequency signal and in response to the supervisory signal causes the telephone line so be coupled to the station unit. Electrical audio baseband frequency signals are converted to an infrared energy beam for transmission to the terminal unit where it is sensed and reconverted to an electrical audio baseband frequency signal which in turn is used to excite a transducer to produce an audible signal corresponding to the audio signal on the telephone line. |
