RF jack 
Radio frequency jack. Audio/video connection commonly used to bring signals from antennas, cable systems, and satellite dishes to components with some type of tuner, such as cable boxes, cable modems, HDTV set-top boxes, VCRs, satellite receivers, TVs, and so on. It can carry video and stereo-audio information simultaneously. When used to connect two components, such as a VCR and a TV, RF provides the lowest video quality of any connection. RF cable connectors usually screw or push onto the jack. Also called F-type, 75-ohm, or coaxial connections.