Node equipment

Node equipment including an optical amplifier that optically attenuates received wavelength division multiplexing signals, and an optical multiplexer/demultiplexer that carries out optical multiplexing/demultiplexing of the wavelength division multiplexing signals received from the optical amplifier via an optical cord, the node equipment comprising:

• an output level detector that detects an optical power level of the wavelength division multiplexing signals at a pre-stage of the optical cord;
• an input level detector that detects an optical power level of the wavelength division multiplexing signals at a post-stage of the optical cord;
• a deciding circuit that calculates a loss of an optical power level through the optical cord from the optical power level detected by the output level detector and from the optical power level detected by the input level detector, and, when the calculated loss of the optical power level exceeds a threshold, determines that the optical cord has an abnormality;
• and
• a controller that controls a signal light wave demultiplexed and passing through the optical multiplexer/demultiplexer to be optically attenuated when the optical cord is determined as having the abnormality.

Node equipment including an optical attenuator that optically attenuates received wavelength division multiplexing signals, and an optical multiplexer/demultiplexer that carries out optical multiplexing/demultiplexing of the wavelength division multiplexing signals received from the optical attenuator via an optical cord, the node equipment comprising:

• an output level detector that detects the optical power level of the wavelength division multiplexing signals at a pre-stage of the optical cord;
• a reflection level detector that detects a reflected power level from an output optical connector connected to the optical cord at the pre-stage of the optical cord;
• a deciding circuit that determines whether a connection state of the optical cord has an abnormality from the optical power level detected by the output level detector and from the reflected power level detected by the reflection level detector;
• and
• a controller that controls the optical attenuation of the optical attenuator in accordance with the decision result by the deciding circuit.