| 摘要 |
PURPOSE:To attain the use of lots of control channels by using part of bits of synchronization bit pattern for synchronization monitor as a synchronization bit alternate pattern after the establishment of synchronization and assigning and using excess bits as a control channel. CONSTITUTION:When its own station detects a synchronization bit pattern at a head of a frame sent from an opposite station, an opposite station alarm 2 is cleared and sent to the opposite station to notice synchronization establishment. Upon the receipt of it, the opposite station sends a frame comprising a synchronization bit alternate pattern 3 and a control channel 4 succeedingly. Thus, its own station implements synchronization monitor using the synchronization bit alternate pattern 3 and transmission of control information using the control channel 4. On the other hand, when an error is consecutive for a prescribed synchronization protection stage number or over, its own station discriminates it to be out of synchronism. Then the alarm 2 in the frame is set to inform occurrence of a fault and uses again the synchronization bit pattern to implement synchronization establishment. |
