tonberry1: Mm, so no external hub needed?
Yes and no :-) It can work without a hub or with a powered hub. I have added batteries and can use it without a hub as it will supply the necessary 5 volts to the 770 to let it know a USB device is plugged in as well as powering the keyboard. It's a bit neater that chopping cables up to hook up power. I disconnect the batteries when plugging it into the hub. People are going the modified cable route so they can plug in other devices besides a keyboard. In my case I've now modified a hub to supply power to the 770 so there's no need for cable modifications.