The BNC connector is used for composite video on commercial video devices. Consumer electronics devices with RCA connector jacks can be used with BNC-only commercial video equipment by inserting an adapter. BNC connectors were commonly used on 10base2 thin Ethernet network cables and network cards.BNC connections can also be found in recording studios.
Following this, attach the green cord from the subwoofer to the green input jack in the computer. At this point the computer's sound card should recongize the speakers. It may be that you will have to configure the computer for the speakers, particularly if you have a 4.1 or 5.1 system.