Patent ID: 8774623

Claim:
A Passive Optical Network (PON) system, comprising: a plurality of Optical Network Terminals (ONTs) for outputting optical signals in time slots allocated thereto in a time division access control manner and having at least one virtual ONT; and an Optical Line Terminal (OLT) for receiving the optical signals output from the plurality of ONTs in the time division access control manner, and detecting an optical power level in a time slot allocated to the virtual ONT, thus determining whether a faulty ONT is present, wherein the OLT comprises: a Microcontroller (MCU) for allocating unique Logical Link Identifiers (LLIDs) and a Virtual Logical Link ID (V-LLID) to the plurality of ONTs and the virtual ONT, respectively; an optical reception unit for receiving the optical signals from the ONTs; a photoelectric conversion unit for converting the optical signals received from the optical reception unit into electrical signals; an optical monitoring unit for converting the signals, which have been converted into the electrical signals by the photoelectric conversion unit, into digital signals, and then detecting optical power; a database (DB) unit for storing data about optical power of the ONTs; and a control unit for allocating time slots in accordance with respective time schedules of the ONTs, comparing the optical power data detected by the optical monitoring unit with the optical power data of the DB unit, and then determining whether a faulty ONT is present.