CPC H04J 14/08 (2013.01) | 11 Claims |
1. A station-side device comprising:
an optical communication interface to transmit and receive optical signals by time division to and from a plurality of subscriber-side devices; and
processing circuitry to
monitor the optical signals received by the optical communication interface,
detect a state in which the optical signals are being received for a predetermined period or longer as abnormal light emission in which the optical signals from one or more of the subscriber-side devices are not received,
sequentially select a subscriber-side device one at a time from the plurality of subscriber-side devices other than the one or more subscriber-side devices as a target subscriber-side device,
test whether or not the abnormal light emission is resolved by stopping transmission of the optical signal from each target subscriber-side device via the optical communication interface, and
specify, if the abnormal light emission is resolved, the target subscriber-side device being tested as a causative subscriber-side device, the causative subscriber-side device being a subscriber-side device that is a source of the abnormal light emission.
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