FiOS Phone - Determine if You Have a NID or an ONT A NID (Network Interface Device) or ONT (Optical Network Terminal) is a Verizon box usually located on the outside wall of your house. This is where the Verizon telephone network connects to your house. An NID is used with copper-wire phone lines while an ONT is used with Verizon FiOS service. If the box on the outside wall of your house looks like the picture below, you have a NID.
Your next step is to complete the test procedure for a NID to determine if the phone problem is with the inside wiring. If the box on the outside wall of your home looks like the picture below, you have an ONT.
Your next step is to check the Battery Back-Up unit* of the ONT, then determine if the ONT has power.
If an active battery is inserted in the Battery Back-Up unit*, it is operating normally and the ONT is powered correctly, complete the test procedure for an ONT to determine if the phone problem is with the inside wiring.
You can use the Verizon Troubleshooter to diagnose your telephone's problem and request a repair if an issue is detected.
Watch the online Verizon Troubleshooter tour
FiOS Phone Service may not be available in all areas.
*Important Note The Battery Back-Up Unit is designed to use a 12-Volt 7.2 Ah SLA (Sealed Lead Acid) battery. Use of a different battery type is not recommended since other battery types may impact the performance of your FiOS services. Verizon is not responsible for damages which result from use of an improper battery. Batteries may be obtained at verizon.com/fiosaccessories or at a third party retail vendor.
See also: Related FiOS Phone Service topics