When breaking down of SDH transmission transmission path non hit change system and manner

摘要

PROBLEM TO BE SOLVED: To evade a short break resulting from a protection time by detecting abnormality of a frame, holding error presence/absence information and signal break presence/absence information at any time, changing signal break absence information into signal break absence information, and switching transmission lines by the transmission lines and by frames according to the error presence/ absence information and signal presence/absence information from a holding means. ;SOLUTION: A warning decision part 20 is provided with a warning decision part 20A for a 0-system main signal and a warning decision part 20B for a 1-system main signal. The warning decision part 20A inputs B3-byte error presence/absence information 21 detected by a trigger generation part, P-AIS presence/absence information 22, and a frame pulse 11 generated by a frame pulse generation part and passes its result as selection information on the 0- system main signal to a selection part 7. The warning decision part 20A is provided with shift registers for holding multiple frames of the B3-byte error presence/absence information 21 and P-AIS presence/absence information 22 in frame units.;COPYRIGHT: (C)2000,JPO