Yeah, Wilso's pretty much got it. RF, or Radio Frequency, refers to signal of the type transmitted and received over-the-air, antenna signal, generally very low energy (micro volatage and amperage), as opposed to baseline, or A/V composite or component signal, which is of relatively higher energy (a volt or two, at a few hundred milliamps). In order to be displayed, or rendered through a speaker or headphone, an RF signal must go through a tuner, be amplified, separasted into its respective audio and video componets, and be converted to an A/V (Audio/Video) signal. An RF connector commonly is of screw-connector collar-and-barrel type (usually called an F-Connector), with a solid center conductor, or, more rarely now, may be a simple wire-and-srew binding connection, while composite (typical A/V - the Yellow Connector in most instances) commonly is a sleeve-type connector most often referred to as an RCA or Phono connector, which plugs directly into a suitable jack. S-Video and Component Video signals are essentially more differentiated refinements of A/V signal. There are RF and baseline connector variations, such as DIN, BNC, TNC, Motorola, PL-xxx and S-Cart, and all sorts of stuff involving impedence, inductance, reluctance, cross-talk, noise, shielding, wave-form, phase shift, velocity propagation, yada-yada-yada, but nevermind. If you want more detail, just holler. I can bore you with more than you possibly might want to know unless you were going for a broadcast license.