DIY: Home Phone Wiring

Written by chris deziel Google
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DIY: Home Phone Wiring
Telephone wires carry a very small electric current. (telephone pole image by robert mobley from

Despite the bewildering collection of coloured wires in a telephone cable, there isn't anything intimidating about home telephone wiring. When connected, the wires carry such a small electrical current that you can handle them bare-handed without fear of a shock. The colours on the wires and jacks follow a standardised code, and if you keep to it, it's almost impossible make a wrong connection. In fact, the most difficult part of telephone wiring is running the cables themselves. For this, you may need a drill and a few hand tools.

Skill level:
Moderately Easy

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Things you need

  • Telephone jacks
  • Phillips screwdriver
  • Drill
  • 3/8-inch drill bit
  • Cat5 telephone cable
  • Utility knife

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  1. 1

    Plan the location of each telephone or Internet connection in the house. Drill holes as needed at each location with a 3/8-inch drill bit so you can run telephone cable to a jack at every location. Unscrew the covers from as many jacks as you need, then screw the back of a jack to the wall or baseboard at each location.

  2. 2

    Run Cat5 telephone cable between the jack for the main phone in your house to the Network Interface Device (NID), which is the interface between the power company's lines and yours. It is usually located on the side of your house. If you can't find it, follow the overhead phone lines to the place they drop down.

  3. 3

    Run cables from the auxiliary jacks, either daisy-chaining them together or running each separately to the NID. If you daisy-chain them, you'll use less cable, but if the first phone in the series goes out, all the other phones will, also. By running all the cables directly to the NID, each phone will work independently of the others. If any of the jacks connects to a separate phone line, run a cable from that jack to the NID.

  4. 4

    Open the customer's half of the NID with a Phillips screwdriver and pull back the door on the telephone module inside. If you have more than one phone line, or you have a separate DSL connection, there will be a module for each line. For wiring purposes, label the main phone line "Line 1," and the auxiliary lines "Line 2" and "Line 3."

  5. 5

    Feed the cables through the bottom of the NID and strip about 10 inches of sheathing from the end of each with a utility knife. Identify the cable going to the main jack and strip 1/2 inch from the ends of the blue and white wire pair. Connect the white wire with blue stripes to the green terminal on the "Line 1" module. Loosen the terminal screw with a screwdriver, wrap the wire around it, and tighten it. In the same way, connect the blue wire with white stripes to the red terminal.

  6. 6

    Add the blue and white pair from any other cables going to jacks that you want connected to "Line 1" to the same terminals.

  7. 7

    Connect the orange and white pair to the terminals in the "Line 2 "module if you have a two-line phone. If you have a jack that can accommodate three lines, connect the green and white pair to "Line 3." Using the orange and white pair for "Line 2" and the green and white pair for "Line 3," add the wires for other jacks you want to connect to modules 2 and 3. When you are done. twist together the unused wires and push them into the NID, then screw the door closed.

  8. 8

    Make connections at the main jack. Connect the blue and white pair to "Line 1." If the terminals aren't coloured, they will be identified as "T," which means tip, and "R," which means ring. "T" corresponds to the green terminal and "R" to the red one. If you are daisy-chaining, connect the blue and white pair to the auxiliary jack to the same terminals.

  9. 9

    Connect the orange and white pair to "Line 2" and the green and white pair to "Line 3," adding auxiliary wires to the terminals if you are daisy-chaining. When you have made all the connections, screw the cover onto the jack.

  10. 10

    Move down the line and make connections at each auxiliary jack in the house.

Tips and warnings

  • Use Cat5 cable, identified by the striped colours on the wires, rather than older cable, which has solid colour wires. It allows for less crosstalk, which is important if the wires carry a DSL signal.
  • If you are wiring a three-line jack, the terminals for "Line 1" are in the middle, "Line 3" on the outside and "Line 2" between them.
  • While you cannot get a dangerous shock from telephone cable under normal circumstances, you can be electrocuted if you are working on your wiring during an electrical storm.

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