How to Install Multiple Phones in Your House

by Chris Deziel

Whether you have one telephone in your house or 10, you must connect each one to the network interface device, or NID, which is the box outside your house in which the lines from the telephone company terminate. The NID can accommodate several different phone lines. You can wire each line to a separate telephone or connect more than one phone to a particular line by daisy-chaining them or branching the wires out from the NID. Telephone wiring isn't difficult, it's safe and it doesn't have to be confusing, as long as you keep track of the wire colors.

1

Find the NID. It's usually located on the side of the house underneath the point where the phone line drops down. Open the cover with a Phillips screwdriver and inspect the modules. There is one module for each telephone or DSL connection you have, and the telephone number is marked on the cover. If it's a pure DSL line, the cover will probably be labeled as such.

2

Choose a suitable location for a jack and plot the path of the telephone cable between it and the NID to minimize the amount of cable you have to run behind walls and other hard-to-reach places. In most cases, it's easiest to run the cable through the basement or crawl space, drill a hole in the floor underneath the jack and pass the cable through the hole.

3

Run a telephone cable from the NID to the location of the jack for the primary telephone and staple it to joists or siding along its path with wire staples to secure it. Unless you plan to install more than two phone lines at that location, use four-conductor cable and a four-pin jack to avoid wiring confusion. You'll get better phone reception and a better DSL connection if you use Cat5 telephone cable. The wires have striped instead of solid-colored insulation.

4

Strip the cable at the NID, separate the wires and expose the ends with a sharp knife. Use the blue/white pair to connect the primary telephone line and the orange/white pair to connect the secondary one. If you are connecting more than two lines to the same jack, use the green/white pair in an eight-conductor cable for the third line and the brown/white pair for the fourth. Connect the white wire with solid stripes to the green terminal in the NID and the solid wire with white stripes to the red one. This is the convention that the telephone company uses, and if you also use it, you will avoid confusion when you have to make repairs.

5

Keep the same color scheme when you connect the wires to the jack, using the blue/white pair for Line 1, the orange/white pair for Line 2 and so on. If the jack terminals aren't color-coded, the one marked "T" corresponds to the green terminal in the NID, and the one marked "R" to the red one. The Line 1 terminals are marked "T1" and "R1" respectively, while those for Line 2 are "T2" and "R2."

6

Wire a different jack to the same phone line or lines in one of two ways. Either run a separate cable from the NID to the new jack and connect the wires to the same terminals in the NID to which you connected the first jack, or run a cable from the first jack to the new one. If you use the second strategy, called branching or daisy-chaining, maintain the same color scheme you used when you wired the first jack to the NID. In other words, use the blue/white pair for Line 1, the orange/white pair for Line 2 and so on.

Tips

  • If you use cable with solid colored wires, the following color convention applies: T1 = green; R1 = red; T2 = black; R2 = yellow.
  • It's usually easier to wire a new jack by daisy-chaining from an existing one, and it uses less cable, but the lines are easier to repair if they all lead back to the NID.
  • If your phone stops working, test the connection at the module by plugging a test phone into the built-in jack. If it's working, check your wiring. If it isn't, call the phone company.

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About the Author

Chris Deziel has a bachelor's degree in physics and a master's degree in humanities. Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since 1975. As a landscape builder, he helped establish two gardening companies.

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