PURPOSE: To construct the economic trunk by placing the address conversion circuit in the monitor trunk circuit and changing the conversion content of the conversion circuit in the case of changing the accommodating position, position of monitoring information, the multiframe synchronizing pattern, and etc.
CONSTITUTION: The input signal in which the monitoring signal and the multiframe synchronizing bit are multiplexed makes access the address conversion circuit 6 by making the circuit number and the time slot number as address in the multiframe synchronizing circuit 5, and the writing of the monitor signal is carried out in the primary memory 2. Further, by the control of the control circuit 7, the access to the same address of the primary memory 2, the secondary memory 3 and the third memory 4 is carried out to perform the reading. These outputs are inputted to the majority determination logic circuit 8 and the output information 9 is obtained by the majority determination. The memory access time is changed and the time constant of error protection can be changed. Further, the output information is memorized once again, thereby the change detection being carried out automatically.
MIYOSHI TATSUROU
SHIRASAWA SUSUMU
KATOU TAKAO
TAKAHASHI MICHIO
OKI ELECTRIC IND CO LTD
NIPPON ELECTRIC CO
HITACHI LTD
FUJITSU LTD