| 摘要 |
PURPOSE:To block invasion of lightening surge from a communication line to a terminal equipment and to attain sure communication between the communication line and the terminal equipment by providing two light emitting elements in response respectively to a signal from the communication line and a signal coming from the terminal equipment and two photodetectors converting the light from the light emitting elements into an electric signal. CONSTITUTION:With a signal sent from a communication line 10, the signal is fetched by an adaptor main body 21 and a light emitting diode 24a is lighted or turned off. With the light emitting diode 24a lighted, the light is sent to a photo transistor(TR) 25a at the terminal equipment 40 via a transparent resin rod 22a and a photo TR(PT) 25a is turned on. When a signal comes from a CPU 41, the TR 44 is turned on/off. With the TR 44 turned on, the light emitting diode 24b is lighted and the light is sent to the PT 25b at the adaptor main body 21 through the transparent resin rod 22b to turn on the PT 25b. Thus, even if a lightening surge is exerted onto the communication line 10, the inversion of the lightening surge to the terminal equipment 40 is blocked. |
