BNC (Bayonet Neil-Concelman or British Naval Connector) A BNC (Bayonet Neil-Concelman, or sometimes British Naval Connector) connector is used to connect a computer to a coaxial cable in a 10BASE-2 Ethernet network. 10BASE-2 is a 10 MHz baseband network on a cable extending up to 185 meters - the 2 is a rounding up to 200 meters - without a repeater cable.