How to Test Your Copper Phone Line (NID) How to Test Your Copper Phone Line (NID) You can isolate your phone problem to your inside or outside wiring by testing your Network Interface Device (NID).

An NID is a small Verizon box generally located on the wall outside the premises. Some older devices may look different from the pictures below. However, you should be able to follow the same procedures.

You will need a screwdriver, a telephone to connect to the NID, a flashlight, and a copy of this procedure.

Note Although the lines are grounded, do not open the NID or test the lines during rain, a thunderstorm, other hazardous weather conditions, or if there is water pooled on the ground near the NID.

Click the picture for an enlarged view and detailed instructions.

1. Open the Network Interface Device. You may have to remove a screw first.
   
   
2. Open the latch inside the box. Locate where your phone lines plug into a jack connection. Unplug the clip of the line that is experiencing trouble. You may have to remove a screw first.Unplug the line that is not working.
   
   
3. Connect a working telephone to the jack on the Network Interface Device.
   
   
   • There is no dial tone
     The problem is with your outside wiring. Verizon will fix the problem at no charge to you. You can use the Verizon Troubleshooter to diagnose the problem and request a repair if an issue is detected.
   
   
   • There is a dial tone
     The problem is somewhere in the inside wiring or jacks. You have the option to repair your wiring yourself or you can use the Verizon Troubleshooter to diagnose the problem and request a repair if an issue is detected.
   
   
4. Unplug the phone, plug in the voice line, close the cover to the NID, and replace the screw.

Watch the online Verizon Troubleshooter tour

See also: Related Troubleshooting Procedures topics