Telephone Network Interface Device (NID)

The telephone network interface device typically refers to the junction box mounted by your telephone service provider on a wall just outside your home. Here are some basic information about your telephone network interface device:

• It is the point where the telephone company terminates their responsibility.
• You are responsible for installing the wires starting from the NID to each telephone jack inside your home.
• To locate the box, simply trace the line that runs from the utility pole into your home.
• The NID is made of hard plastic and is weatherproof.
• Unplugging the short cable inside the NID from its jack will disconnect power and signals from the telephone company.
• Plugging a working telephone into a jack inside the NID will allow you to know if there is power and signals running from the telephone company into your household wiring.
• The NID is maintained by the telephone company.
• The red and the green wires running from the telephone jack inside your home connects to similar colored terminals inside the jack.

          Reference: Public Service Commission of Wisconsin: Testing, Repairing and Installing Home telephone Wiring - Locating the Demarcation Point