A RJ-45 Ethernet connection is required for your Fyre BoXXX if you are not using a WIFI Fyre BoXXX. If your computer is equipped with an Ethernet card, you could use the “Internet connection sharing” application in Windows to configure your computer as a “soft router”. If Windows cannot be configured as a “soft router” you need to use a modem that has a RJ-45 connection which will allow the Fyre BoXXX to directly connect to the modem or home router.