Using Gadget/Gadget II with Net3 Concert

Do I have to be connected to network for Net3 Concert software to discover devices plugged into the Gadget/Gadget II?

No you do not.  The Gadget/Gadget II does not require network connection to discover devices.  However you do need to make sure that Net3 Concert Software has discovered your Gadget.  check in the bottom right-hand corner of the Net3 Concert screen.  "Gadget (#): [serial_number]" will be listed there if it is properly detected.  if you do not see this in the bottom right corner, follow the steps in this article to make sure the drivers are properly installed.  Manual Installation of Gadget and/or ETCnomad Dongle Drivers on Windows