The Optical Network Terminal (ONT), sometimes generically called a router, is the powered electronics that goes inside the house, connects to the fiber network, and gives you an Ethernet and/or WiFi connection to the Internet. It looks very similar to a coax cable or DSL router and it performs the same function. Instead of a coax or copper WAN connection, it'll have a fiber connector.
The ONT can provide more services than 1 Gbps Ethernet and WiFi. It can also provide one or two voice ports to provide dial tone within the house. It can even have a coax cable output to provide TV service. In the modern world of unbundled, over the top services, a small community would be well served to just provide Ethernet and let other companies provide other services.
The ONT/router must be matched with the central office Optical Line Terminal. They must speak the same communication protocol. Sometimes you will buy your OLT and all the ONTs from the same vendor, other times, more common with a point-to-point network, you can use different manufacturers for the OLT and ONT.
Note that most modern houses will need more than a single WiFi access point, so having WiFi bundled into the ONT/router isn't necessarily a good thing. Most houses would be better served by installing a Google WiFi or similar system that has multiple access points spread through the house.
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