Patent ID: 6778781
Filing Date: 2004-08-17
Classification: H04B,H04J

Abstract:
In an optical network comprising an optical splitter connected to (1) a working optical subscriber unit (OSU) of a working circuit via a working optical fiber, (2) a protection OSU of a protection circuit via a protection optical fiber, and (3) one or more optical network terminals (ONTs), wherein the protection OSU has a protection burst mode receiver (BMR) configured to receive an upstream optical signal from the optical splitter, a method for determining whether the protection OSU is functioning improperly, comprising the steps of:(a) applying a BMR reset pulse to the protection BMR at a particular timing position; (b) attempting to interpret a current upstream cell in the upstream optical signals received at the protection BMR to identify a valid set of data in the current upstream cell; and (c) repeating steps (a) and (b) one or more time for one or more different upstream cells using a different timing position for each BMR reset pulse until the valid set of data is identified in the current upstream cell, wherein the protection circuit is determined to have failed if the valid set of data is not identified within a specified duration.