| 摘要 |
PURPOSE:To obtain accurate ad stable transmission performance even when an optical signal transmission line is formed like a multi-drop type by providing the transmission line with a distributor or the like for detecting the existence of an electric signal outputted from a photoelectric converter and sending or stopping the electric signal to an electro-optical converter. CONSTITUTION:When a signal A is outputted from a transmission terminal TX in a terminal station 1A and signal outputs from terminal stations 1B, 1C are '0', the signal A is converted into an optical signal by an electro-optical conversion part 7 and reconverted into an electric signal by the photoelectric converter 10 through an optical fiber 3A1. A detector 1-3A in the distributor 12 receives the signal and turns its output to '0', an OR circuit 14 outputs '1' and both detectors 13B, 13C output '1'. Thereby, an AND circuit 15A outputs '0' independently of the signal outputted from the circuit 14 and AND circuits 15B, 15C output the signal of the circuit 14 as it is, so that the signal A is transmitted to respective receiving terminal RX of the stations 1B, 1C through optical fibers 3B2, 3C2. Consequently, accurate and stable transmission can be executed even when the transmission line is formed like a multi-drop type. |
