| 摘要 |
PURPOSE:To simplify each terminal equipment and to quicken the deciding operation by providing a circuit detecting the presence of a transmission signal from each terminal equipment and the presence of generation of collision in an optical star coupler, and a transmission gate to be turned off only when the absence of collision of transmission signals in detected. CONSTITUTION:A transmission signal presence detecting circuit 10 generates an ON signal when a transmission signal exists and the ON signal is inputted to a transmission section 11 and a collision presence detecting circuit E. An output signal from transmission signal presence detecting circuits 10... in all channel sections C1, C2... are inputted to the collision detection detecting circuit E. When plural ON signals are inputted at the same time as the input signals and a collision between the transmission signals from plural terminal equipments occurs, it is detected and a collision generation detecting signal is generated. Only when the presence of the signal is decided by the transmission signal presence detecting circuit 10, and decided that no collision occurs by the collision presence detecting circuit E, a transmission gate of an amplifier 11c is closed and no output is generated. |
