Adding a Second Phone Line
Upgrade your phone system without shelling out big bucks to the phone company
A surface-mounted jack is simple to install.
Homeowners rarely attempt to work on their own phone system — but they should. Projects such as installing a new line are fairly easy to do, the work is relatively safe, and you probably have most of the tools on hand. Best of all, you can save yourself a bundle. In many areas, you pay $40 or more just to have a phone company installer show up at your house. Then it can cost $15 to $20 for every 15 minutes the installer is there. And electricians who do phone work aren't any cheaper.
We'll show you how to install a second phone line — not another extension but a line with its own dedicated number. Another line comes in handy for a home business and Internet use, and to keep your kids from tying up the phone you use. What you learn from this project will help you with other upgrades and repairs.
How to Add a Second Line
The first step to adding a line is to contact the local telephone company and request a second line. The company will make the required wiring changes at your Network Interface Device. What's a NID? It's the junction box, usually located outside your house, where the phone company's lines end and the wiring for your home begins. If there's no NID at your home, the phone company will make the proper connections at a demarcation box. You can request to have a NID installed, which will make it easier for you to troubleshoot certain problems with your phone wiring. Having an exterior NID also means that if the phone company needs to do repairs or upgrades, a technician can do so without your having to be at home.
You probably aren't aware of it, but the phone wiring in your house can already handle two separate lines. A single line requires two wires, or conductors. Standard residential phone cable contains two pairs of wires, which is enough for two separate lines. The first line is usually made up of the wires covered with red and green insulation; the yellow and black wires serve the second line.
If you live in a newer a house or a house where new telephone cable has been installed, you may encounter "Cat 3" or "Cat 5" cable. Both types contain four pairs of wires — enough for four separate phone lines. The paired wires for a single line are usually twisted together, and they consist of a solid-color wire with a white spiral, or tracer, and a white wire with a tracer that matches the solid color.
Quick Splices With UR Connectors:
With these small devices, a new branch phone line can be added to an existing line with no stripping, splicing, or junction box. Simply insert the color-matched wires into the connector and squeeze the red dot to secure the connection.
Pick Your Spots
Adding a second phone line means you will need to decide whether to use your existing phone jack or add a new jack in a different location. To check if an existing jack is already wired for two lines, unscrew the cover plate and examine the terminals where the wire from the cable is connected. If just one pair of wires is connected, your jack is wired for a single line only.
To hook up the second line, strip about 1/2 inch of insulation from an unused pair of wires (the yellow and black wires, if you're working with standard cable) and loosen the screws from the corresponding terminals. Wind each bare wire in a clockwise direction around the terminal screw, then simply tighten the terminal and replace the cover.
Because it's so thin, phone wire can easily be weakened or broken if you're not careful when stripping it. "You don't want to cut into the wire at all," explains David Albanese, an electrician and phone technician based in Bangor, Pennsylvania. "Homeowners who are used to stripping heavier-gauge 120V cable often end up weakening phone wire during the stripping process, which can result in a broken wire later on."
Albanese recommends simply nicking the insulation lightly with a knife at the place where you want to strip it off. It's not necessary to cut all the way around the insulation. The next step is to insert your thumbnail into the nick you made, pinch the wire between your thumb and forefinger, and pull the insulation off. With a sharp, strong thumbnail, you can even skip the knife nick. A couple of practice runs on some scrap wire, and you'll have the technique down.
At this point you should have two-line service at one jack. If you are going to use a two-line phone at this location, just plug it in. If you are going to use two different devices, buy a duplex adapter ($2.50), a modular plug that has slots for both lines.
Another option is to replace a single jack with a two-jack wall plate. Or, install a second jack a few inches away from the first and connect the two with a short piece of cable. Both of these are more secure options because they don't rely on an adapter that could fall out, and they give each jack its own line. One drawback to installing a second jack near the first one is that it leaves extra hardware on the wall.
Phone cable can be run through walls and floors easily
Test Your Work
No dial tone means one of two things: Either both pairs of conductors aren't wired to the jack's baseplate, or the jack you're working on shares the cable run with other jacks that are wired for one line only. If this is the case, check these other jacks to make sure both pairs of conductors are attached on all of them.
That's the neat and clean version of installing a new line to an existing jack, and it works. But previous work on your lines can complicate the situation. For example, an extension to the same line you're working on could have been run back to the NID or demarcation box independently and connected to the same terminal as the jack you're wiring. Although it can be confusing, this independent wiring run won't affect the work you're doing.
Thin, low-power phone wire can be run along baseboards or under carpet.
Adding an Independent Line
The other option for installing a second line, as discussed above, is to put in a new jack and run cable back to the NID or demarcation box. The main benefit here is that problems with your existing phone lines will not affect service on a new line that connects directly to the NID. The drawback is that you will need to snake the cable through walls to keep it out of sight. Use only round telephone cable, and where it is exposed, anchor it every 6 to 10 inches. You can buy a staple gun that shoots crowned staples for phone cable, or use plastic cable straps, which you install with a tack hammer.
The most common jack is a square, surface-mounted version that is often screwed to baseboard molding, although it can be installed against any wall surface. This type of jack has a mounting plate with four terminals, labeled R, G, B, and Y (red, green, black, and yellow). Attach the wires as shown on the image.
Extending a Line
Once you know how to hook up a new line, it's not a big deal to move the location of a jack or add an extension. Just run the cable between the original jack and the new one, and make the connections.
Thanks to its small diameter and low voltage, phone cable is less noticeable and easier to conceal than electrical cable. You can often run it under the carpet, along molding or trim or inside cabinets and closets (see illustration). Just remember to keep cable out of damp locations and away from sharp edges.
Another option is to tap into an existing cable run in an attic or basement with a UR connector. With these devices, available at home centers and electronics stores, you simply insert mating wires into the holes and compress the red dot with pliers to make the connection. Just make sure you are splicing into the right line.
No matter what type of phone upgrade or repair work you undertake, there's an easy way to check your work: Simply plug in a working phone, pick up the handset and listen. A clear, static-free dial tone signals success — and significant savings over what the telephone company would have charged you.
Common Problems, Easy Answers
Here's what to do if you encounter . . .
Old four-prong phone outlets: Adapters are available to convert old outlets to modular jacks, but it's almost as easy to install new modular jacks. Just disconnect the wires from the old jack and attach them to the terminals on the new one.
Static on the line: Determine if the problem is with your wiring or with the phone company's by testing at the Network Interface Device.
After unplugging the jack that connects your interior cable, plug in a phone. Lift the handset, listen for the dial tone, and make a local call. If you get static, the problem is with the exterior line, and you need to report it to the phone company. If the tone is clear and there's no static, this means the problem is with an interior line, and it's your responsibility to fix it. If you recently added a new line, check the modular plugs. On higher-quality plugs, gold-plated contacts ensure optimum transmission. Cheap, unplated plugs are prone to corrosion, especially in damp locations. Try replacing the plugs you added with gold-plated, UL-listed ones.
Phone wires carry only a very slight charge, but there are a few things to watch out for. Take the phone off the hook to disconnect the line you're working on. Or, disconnect the main feed line at your demarcation box or Network Interface Device. Avoid working on phone wiring if you have a pacemaker, or if there's an electrical storm threatening. Finally, make sure you are aware of any electrical cables (120 and 220V wires) whenever you are cutting into a wall or snaking phone cable.
Where to Find It:
100 Throckmorton Street, Suite 1800
Fort Worth, TX 76102