| 摘要 |
PURPOSE:To prevent the breaking of a circuit completely by selecting a transmission part in normal operation by a selection part which detects the operation state of the transmission part when a controller is detached from a frame, and connecting the transmission part to a high frequency switch. CONSTITUTION:While the control part which detects one device becoming abnormal in a multiplex transmission device and switch the high frequency switch SW part 31 to a normal device side is detached from the frame, a control signal is sent out to the SW part 31 from neither terminal 8-1 nor 8-2. A terminal 20 which is grounded is released. If one of two transmission parts troubles and a transmission trouble signal arrives, the terminal 21 or 22 is grounded, so the selection part 23 identifies the transmission part in trouble. The selection part 23 detects signals from the transmission parts to select the transmission part in normal operation and sends its selection output to the SW part 31, so that the selected transmission part is connected to an output terminal 10. |
