The OLT serves as the starting point of a PON, connecting to the core switch via an Ethernet cable. Cisco introduces GPON with the Catalyst GPON platform. Optical Distribution Network (ODN) - The physical fibre and optical. In short: The OLT (Optical Line Terminal) is the central control unit of a Passive Optical Network (PON). It converts data signals, manages bandwidth, and connects hundreds of users over a single optical fiber infrastructure. Typically placed at the central office to provide a fiber optic interface to the user's passive fiber optic. A GPON system consists of the Optical Line Terminal (OLT), Optical Network Unit (ONU), and Optical Distribution Network (ODN). Depending on the access scenario,ONUs can be deployed in corridors. In a PON network, an OLT is deployed at the service provider's central office, and many ONU devices or optical ONT devices and optical splitters (SPLs) are near the end users. In addition, ODNs are used for data transmission between OLTs and ONUs/ONTs.
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