Complex sentence: An Ethernet network controller typically has a RJ45, BNC, or AUI socket where the network cable is connected, and a few LEDs to inform the user of whether the network is active, and whether or not there is data being transmitted on it.
Split into simpler sentences: An Ethernet network controller typically has a RJ45 socket where the network cable is connected. A few LEDs inform the user of whether the network is active, and whether or not there is data being transmitted on it.