| 摘要 |
PURPOSE:To improve the stability of signal transmission by preparing another transmission line connecting both ends of an already provided transmission line and using the prepared transmission line at the time of disconnection of the already provided transmission line. CONSTITUTION:A transmission line 4 is prepared which connects both ends of an already provided transmission line 3 consisting of a current transmission line 1 and a stand-by transmission line 2. Line switching means are provided in both ends of the transmission line 3. Normally, a signal is transmitted through the transmission line 1; and when trouble occurs in the transmission line 1, the signal is transmitted between external input and output terminals of current line switches 6-1 and 6-2 through line switches 6-1, 6-2, 7-1, and 7-2 and the transmission line 2; and when the transmission line 3 is all disconnected, the signal is transmitted between external input and output terminals of current line switches 6-1 and 6-2 through line switches 6-1, 6-2, 7-1, and 7-2 and the transmission line 4. External input and output terminals of stand-by line switches 7-1 and 7-2 are used for not only signal transmission for all disconnection of the transmission line 3 but also signal transmission passing the transmission line 2. |
