Apple restricts use of cheaper compatible composite A/V cables on iPhone and only allows TV-out support via an original Apple cable and that to for only selected applications like iPod and photo slide-shows, if you plugin an non-apple video-out cable in your iPhone you are shown an error "This Accessory Is Not Made To Work With iPhone" and TV-out does not work. Luckily if you have an jailbroken iPhone, not only you can make use of the cheaper non-apple A/V cable for TV-out functionality but also mirror the iPhone display on your TV, meaning you can enjoy all your iPhone applications and games on the big screen.