CEL-FI automatically selects clear, unused channels from the UNII bands (5.15-5.35 GHz, 5.47-5.725 GHz and 5725-5825 GHz) for communication between the Network (Window) Unit and the Coverage Unit. While in some cases these are the same frequencies as Wi-Fi, the CEL-FI system uses a proprietary protocol for communication and is designed to work in harmony with existing wireless devices such as Wi-Fi routers, cordless telephones or baby monitors.