How to Wire a CAT5 for the Telephone

Written by nichole liandi
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CAT5 cable consists of an insulated cable that carries four sets of twisted pair wires--eight wires in all. It's commonly used for computer-network connections and is increasingly common in home-telephone and other wiring applications, since it provides extra capacity beyond what a simple two-wire telephone line has. When CAT5 wiring is used in construction or remodelling, the process of adding second phones and other services is greatly simplified.

Skill level:
Moderately Easy

Things you need

  • CAT5 cable
  • Wire cutters/strippers
  • Screwdriver

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  1. 1

    Strip away the outer sheath of the CAT5 cable, so the four twisted-pairs of wires inside are exposed. Remove about one to two inches of the sheath with your wire strippers.

  2. 2

    Your telephone connection only requires two wires, so select two wires to use as the phone line. Conventions are hardening that the appropriate wires to use are:

    For a primary line -- orange and orange/white For a second line -- blue and blue/white

    It should be pointed out, however, that the actual wires used are unimportant as long as you are consistent. Simply put, be sure to connect the same colour wires at both ends of your circuit.

  3. 3

    Open your telephone wall plate or modular telephone jack. Use a screwdriver in either case, turning the mounting screws on the face to the left to loosen.

    How to Wire a CAT5 for the Telephone
    Modular Jack
  4. 4

    Strip about 3/8 inch of insulation from the ends of the two wires you've chosen to connect to the telephone jack. You'll find two screws in the telephone jack -- loosen them by turning to the left, and slip one wire under each of the screws. Tighten the screws down, and replace the cover of the telephone wall plate or the cover of the modular jack.

  5. 5

    At the terminus of the telephone junction box outside your house, remove the cover by turning the screw on the cover to the left. You'll find two screws, similar to the ones in the wall plates inside your house. Loosen them and slip the stripped wires from the other end of your CAT5 cable under the screws. Replace the cover.

    How to Wire a CAT5 for the Telephone
    Junction box
  6. 6

    Plug a phone into your wall jack or modular connector and listen for a dial tone. If you don't hear one, check the wiring colours and connections on both ends of the circuit.

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