| 摘要 |
PURPOSE:To improve the noise resistance and the insulating performance, by detecting the collision of a transmission signal and a receiving signal by the cooperative operation of a modulation and demodulation device and a repeater installed at plural terminal devices in a data communcation system, and informing the result to the terminal devices. CONSTITUTION:A data transmitted from one of arbitrary terminal devices 1a 1t is converted from an electric signal into an optical signal at the modulation and demodulation device 2, received at a slave repeater 4 through an optical fiber cable 3, the data is transitted from the slave repeater 4 to a high-order master repeater 6 through an optical fiber 5, the repeater 6 returns a receiving data from the slave repeater 4 and transmits it to all the slave repeaters 4, the modulation and demodultion device 2, and a terminal 1. When the receiving signal from the plural terminal devices 1 is detected at each receiver in the slave repeater 4 from the respective modulation and demodulation device 2, a collision signal is generated from the repeater 4, this signal is returned at the repeater 4 and transmitted to each modulation and demodultion device 2. This signal is detected at the modulation and demodulation device 2 and the collision is informed to each terminal device 1. |
