ethernet - RJ45 Cable only has 4 wires - Network Engineering Stack Exchange
Cat 6 Ethernet Cable 15 ft, High Speed Ethernet Cord, Slim LAN Cable with RJ45, Weatherproof Flat Internet Network Patch Cord, Fast Gigabit LAN Wire for Gaming, PS5/4/3, Xbox, Modem, Router - Blumaple LLP
Power Over Ethernet Using 4 Wires (2 Pairs) - YouTube