When everything is working right I have been surprised how many devices I can connect. I've tried thumb drives, external hard drives, DVD/CD drives and have had success writing to DVD-RW, printers, scanners, pc-faxes. A 4G Mobile Wi-Max USB didn't seem to work, but I'm using all of this on Clear Wi-Max modem to my DIR-625 rev C with no problems. I think the powered hub is the secret. I've had all of these connected pretty much all of the time to my home network.