An OLT interfaces with the Metro Ethernet Network or backbone internet, receiving high-speed data which it then transmits to multiple Optical Network Terminals (ONTs) via fiber optic cables. A single OLT may connect up to 128 users (e. The OLT acts as the central controller of a PON system, installed at the service provider's data center or central office. ONT is an ITU-T term, whereas ONU is an IEEE term. In a PON architecture, the. An OLT is a key component in a PON, a high-capacity, cost-effective broadband access solution.