Got the Nikon Coolpix to work. Per Jolouis' suggestion, moving over from "dongle" thread. I got the Nikon to read on the N800. Though the camera was working, I put new batteries in and then took a picture with a newly formatted CF card. That did it. I think the new batteries are what mattered. I'm gonna try a powered hub with the other two devices, and I'll update. Thanks for the reply Jolouis.