RCA connector
The RCA connector was initially used for audio signals. As with many other connectors, it has been adopted for uses other than originally intended, including as a DC power connector, an RF connector, and as a connector for loudspeaker cables. Its use as a connector for composite video signals is extremely common, but provides poor impedance matching. RCA connectors and cable are also commonly used to carry S/PDIF-formatted digital audio, with plugs colored orange to differentiate them from other typical connections.