Gary,
The UM1X was the one I recommended to Charlie. However, the Yamaha does the same exact thing from what I know. It shouldn't matter which one he uses. It is just a matter of getting the right driver into Charlie's computer and knowing what parameters to set on the keyboard to transmit and receive midi data. As much as I know about arranger keyboards, I know very little about hooking up keyboards to computers. I've never wanted to do this because I am not a player using these products outside of my store environment.
Good luck! I'm sure you will get it figured out.
Regards,
George Kaye
Kaye's Music Scene
Reseda, California