Patent ID: 8050554

Claim:
A fault localization apparatus for an optical line in an optical communication network between a subscriber and a central base station which multiplexes a plurality of downstream data signals, the apparatus comprising: a monitoring pulse signal transmission unit configured to modulate a monitoring pulse signal to a signal of a certain frequency band having substantially no interference with a frequency band of the downstream data signals; a switch configured to transmit the modulated monitoring pulse signal to one of a plurality of channels of the downstream data signals; a plurality of couplers each of which is disposed at each channel of the downstream data signals, combines the modulated monitoring pulse signal and a downstream data signal input thereto, and outputs the combined signal to a corresponding downstream light source; and a monitoring pulse signal reception unit configured to detect a position of a fault occurring in the optical line by extracting the monitoring pulse signal from a reflected optical signal input through an optical fiber through which the subscriber communicates with the central base station.