Here are some key sections you might find in the Nokia G-010G-R manual:
The Nokia G-010G-R is a Gigabit-capable Optical Network Terminal (ONT) commonly deployed by fiber internet providers (such as Frontier Communications in the US). Unlike a traditional router, this device is the bridge between the fiber optic cable coming into your home and your personal router. It converts optical (light) signals into electrical (Ethernet) signals. nokia g-010g-r manual