| 摘要 |
PURPOSE:To prevent the influence of trouble in a loop transmission system by connecting a 1-bit delay circuit to an SDLC procedure execution part in parallel, and switching and outputting the output of the SDLC procedure execution part and the output of the 1-bit delay circuit. CONSTITUTION:When an SDLC signal arrives at a secondary station, the SDLC procedure execution part 5 detects a frame 9 addressed to its station and a polling signal 11 successively because the input of the execution part 5 is connected to a signal input part 4, and transfers frame data to a control part 7. At this time, a transmit signal is transmitted to the trailing secondary station through the 1-bit delay circuit 13. Further, the SDLC procedure execution part 5 also sends out the transmitting signal while delaying it by one bit. The control part 7 after receiving the polling signal 11 switches a selector 14 to pass the output of the SDLC procedure execution part 5 to a signal output part 6. The control part 7 monitors the time of the frame transmission of the SDLC procedure execution part 5 and switches the selector 14 to the side of the 1-bit delay circuit 13 forcibly in case of a time-over state. |
