An Optical Network Unit, commonly known as ONU, is a fundamental element in fiber access networks. It serves as the crucial endpoint that links users to the optical distribution network. Functionally, its primary role is to convert optical signals transmitted from the service provider’s network into electrical signals that can be readily utilized by end – user devices such as computers, smart TVs, and routers. This conversion process is the key to unlocking high – speed, reliable internet access for users across different settings.