Not sure what the full technical reasons are but I was strongly advised against the unpowered hub, somehow, they say, it doesn't always do the job intended.. .Bought an Entrega powered hub,with 4 USB, 2 serial and one printer port, about US$80 and connects to one of your existing USB ports.. .Just throwing this in for interests sake, if the unpowered works well then that is great! <img border="0" title="" alt="[Smile]" src="smile.gif" />