The original question,the way I understood is "how to charge to tab at the same time connect to tv and watch movie or make presentation". I was assuming that there is no electrical outlet nearby to plug the charger and connect the usb cable.
As to how long or how short, the specs are all there in the dealextreme website.
I have no intention to defend this cable, My intention in posting this is to inform anybody interested that this is available for a cheap price and I am using it with no problems. If you are not interested to buy an 8 USD cable then you should instead buy the original Samsung AV cable
here