Most use five cables (Horizontal, Vertical, Red, Green, Blue), although 3 cable set-ups are also common. The ends can be RCA (normal style) or BNC (different). Component video is 3 cables, usually RCA ends, but it's still analog, not digital (even in progressive mode). Thus HDTVs have component 3-cable video but that's not used for true digital HDTV signals. The push is for FireWire (which can handle copy protection well apparently) for HDTV, but most TVs do not have FireWire. Of course most HDTVs don't even have HDTV tuners, so there is still a lot to be figured out.