What Is An ONT?
An ONT (optical network terminal) is an outlet to the internet. This device (a small black box) is placed in your office, and serves as the termination point for your connection.
The ONT's job is to convert the light pulses into electrical pulses - but why? Because your internal network runs on electricity, the ONT takes the light from your fiber provider’s network lines and basically acts as a translator.
In practical applications, all this means is that the fiber is terminated in the ONT (the fiber line actually attaches to the box itself) and you then connect your devices (firewalls, switches, additional routers, etc.) into the available ethernet ports on the other side of the ONT.
ONTs can vary in features. They can either act as gateway devices and provide IP addresses to your devices, or they can bridge the connection between your provider and your network.