I've just had BT FTTP installed, and have a fibre coming into the building. They use GPON. It's wired into a modem ("Optical Network Terminal") that Openreach p

I've just had BT FTTP installed, and have a fibre coming into the building. They use GPON. It's wired into a modem ("Optical Network Terminal") that Openreach provide, which then presents the connection via cat5. You then plug your router in, which then uses PPPoE to establish the connection.