OPTICAL LINE TERMINAL AND FAILED TERMINAL IDENTIFICATION METHOD FOR PON COMMUNICATION SYSTEM

A method according to an embodiment of the present invention relates to a failure terminal identification method that can identify an optical network unit ONU having caused a failure in which the optical network unit ONU continuously sends a continuous signal. In the method, timing of upstream burst optical signal transmission is assigned to a plurality of optical network units ONUs connected to a PON communication system, intensities of upstream burst optical signals transmitted from the respective optical network units ONUs are detected and stored in advance, an intensity of an optical signal detected during a period of time ti during which transmission of an upstream burst optical signal is not assigned to any of the optical network units ONUs is recognized as an abnormal light intensity, the abnormal light intensity is compared with each of the stored intensities of upstream burst optical signals from the respective optical network units ONUs, and one or a plurality of optical network units ONUs whose difference in light intensity is determined to be smaller than a threshold value as a result of the comparison is(are) estimated as an optical network unit ONU having caused a failure or as a candidate for the optical network unit ONU having caused a failure, the failure being such that the optical network unit ONU continuously sends a continuous signal.