| 摘要 |
PURPOSE:To prevent occurrence of a discontinuous signal and of a hit at changeover of the transmission line by decreasing a phase difference of a frame caused by a difference from a delay quantity due to a difference from the length of the paths when an NNI frame signal is received via two different paths. CONSTITUTION:A sender side equipment forms a multi-frame with respect to an NNI frame to input data in H4 bytes being a path overhead of a VC-3 or VC-4 and sends the frame to two different paths. a 1st synchronization circuit 3 and a 2nd synchronization circuit 4 for the H4 bytes establish the multi-frame synchronization to detect a phase difference of the signal coming from the two paths, a control circuit 7, a 1st delay memory 5 and a 2nd delay memory 6 give one signal, and the paths are switched uninterruptibly by selecting a selector 8 and the data are outputted from an intra-station transmission interface section 9. |
