How to Wire a Phone Jack for a 2nd Phone Line

Residential dwellings are typically wired with single phone lines and need additional wiring to accommodate another one. The telephone company sends its power and signals up to the NID or network interface device outside your house, and telephone wires for a second line must be installed from the NID into your house. Wiring a second line into your home is easy once you know the basics.

• 1

  Turn off the power to your phone line by unplugging the modular plug from its jack inside the NID. The NID is a junction box placed by the telephone company outside your home. To find the box, follow the line that runs from the utility pole into your house.

• 2

  Pass a telephone cable through the opening at the bottom of the NID and pull the cable up by about a foot. Expose the inner wires by stripping off 3 inches of covering at the tip of the cable, using diagonal pliers. Strip 1/2 inch from the insulation of the black and yellow wires, using a wire stripper.

• 3

  Look for the second pair of green and red terminal screws inside the NID and loosen them, using a screwdriver. A telephone needs two wires to work, which is why there is a pair of green and red terminals for each phone line. The first pair is for line 1 and the second pair is for line 2.

• 4

  Wrap the yellow wire clockwise around the red terminal screw and the black wire around the green terminal screw. Tighten both screws to secure the connection. Run the cable into your house to the spot where you will place your telephone, using cable staples every 12 inches to secure the line. Avoid placing the cable side by side with power lines to prevent poor data transmission.

• 5

  Pull the cable gently out of the telephone outlet box on the wall and cut it after about an extra foot in length. Strip off 2 inches from the cable sheath using diagonal pliers and strip off 1/2 inch of insulation from the red and green wires using a wire stripper.

• 6

  Unscrew the cover of a surface mount RJ-11 telephone jack and loosen the black and yellow terminal post screws behind it. Hook the black wire clockwise around the black terminal post, hook the yellow wire clockwise around the yellow terminal post and tighten the screws to secure the connection. Replace the cover of the jack.

• 7

  Plug the modular connector inside the NID back to its jack to restore telephone power and signals. Plug a telephone into the newly installed jack and listen for a dial tone. Place a call to check the connection.