No, the USB port on the Xfinity Wireless Gateways are NOT active, they are marked as "[Currently Not Available]". Older versions of the manual said "For Future Use", not sure why they changed it, although I'm sure someone will pipe up and say "hey, maybe they are getting ready to activate it!". I'll belive it when I see it. Not sure what exact device you are describing, the devices I see connect to your computer for USB or for power draw to a power outlet. The network interface is wifi or ethernet, so connection to a gateway or router or modem via USB is not likely to work. I haven't read the Nettalk docs since I have no clue what device your're talking about but since they all have ethernet interfaces, it doesn't matter if the USB port on the gateay works or not, just connect via ethernet to one of you open LAN ports on the gateway.