How to Replace Old Telephone Circuit Boxes

Locate the box called the network interface device where the telephone company's wires terminate and the house wiring starts. The box is typically mounted on a wall just outside your home and can be located by tracing the telephone cable running into your home from the utility pole.

Open the NID and look for a short telephone cable plugged into a telephone jack inside the NID. Unplug the short telephone cable from its jack to disconnect power from the telephone company.

Unscrew the cover of the junction box. Loosen the terminal screws inside, then disconnect each wire from its terminal screw. Loosen the screws that hold the box onto a surface, then remove the box.

Attach the new junction box. Loosen each terminal screw inside the junction box. Hook each wire coming from the jacks inside your home along with the wires running from the NID to each terminal screw in the junction box according to the following configuration: wrap all red wires onto red-colored terminal screws, then wrap all green wires onto green terminal screws. If you have a second telephone line, wrap all black and yellow wires to each similar colored terminal screw. Tighten all of the screws to secure each connection.

Replace the junction box cover. Plug the short cable inside the NID back to its jack to restore telephone power and signals into your home. Plug a telephone into a jack inside your home and listen for a dial tone.