The Optical Network Terminal (ONT) is a small network interface device that Nex-Tech has installed on the outside wall of your location. There is a power cable that goes to the inside of your home to a Battery Back-Up Unit that is plugged into a standard AC outlet. You will first want to make sure that this power cable is plugged in and getting power. The Batter Back-up Unit will supply power to the ONT if the power has gone out or if the unit has become unplugged.To check power please locate your Battery Back-Up Unit which is pictured below.Below is a picture of a Battery Back-Up Unit that is fully powered and operational on the inside of the premise. You will see how both lights are lit green.Below is a picture of a Battery Back-Up Unit that has lost AC power but still has battery charge. You can see how the AC light is lit orange and the Output is lite green. Generally this means the AC power adapter has come unplugged from the wall, the AC power adapter has come loose inside the Battery Back-Up Unit, or the circuit on that outlet is not properly working. To test the outlet you can plug a lamp or any device that requires AC power.Below is a picture of a Battery Back-Up Unit that the battery has come disconnected or needs to be replaced.Below is a picture of a Battery Back-Up Unit that has no power. As you can see no lights are lit on this box. Generally this means the battery has no charge and the AC power adapter has come unplugged from the wall, the AC power adapter has come loose inside the Battery Back-Up Unit, or the circuit on that outlet is not properly working.