The cable came in 2 varieties, a YPbPr to VPORT and an xbox to VPORT cable.
It just makes it easier to hook up your xbox to the tv and frees up an input source. That's it. the only place that I know of that has the VPORT cable is directly from RCA. The input is YPbPr component and audio left and right. it's not an RGB input or anything like that.