| 摘要 |
PURPOSE:To prevent line momentary interruption at line switching by connecting both active and spare transmission lines to a reception system device in line switching and disconnecting the transmission line not selected after a prescribed time from the reception system device. CONSTITUTION:Active and spare routes a, b are provided respectively with relays 7, 8, which are switched to a reception section 6 by a line switching control section 10. The line switching control section 10 consists of a line switching device 9 and a delay logic section 11 in which logics to change over the changeover switches 7, 8 based on an output signal SL of the device 9 are prepared. Then both the active and spare routes are connected to the reception section 6 in a short time at line switching and the line switching is applied by disconnecting one route from the reception section 6. Thus, the momentary interruption of the line at switching is prevented completely. |
