Telephone cords contain four or more small wires that would be difficult to strip and connect for a splice. Such connections also make the line vulnerable to static crackling sounds. However, a splice is sometimes the only way to add telephone jacks or expand a home telephone cable layout. Fortunately, there are splicing aids for telephone cords that make solid connections without any wire stripping.
Open the customer access side of your telephone network interface box with a slotted screwdriver. The box is usually found on a basement or outside wall of the house. Unplug the test plugs attached to the connected wires to avoid a shock from incoming calls while you work on the telephone cable.
Make a note of the four wire colours connected to the terminals inside the telephone network interface box. The wires are carrying the signals to the telephone jacks inside the home.
Remove three inches of the outer jacket from the existing telephone cable and the new cable to be spliced onto it by carefully slicing through both the jackets lengthwise from the ends with a utility knife. Pull the individual wires through the slits in the jackets and cut off the empty portions of the jackets.
Pull the wire colours from the existing phone cord that are connected inside the interface box. Push each of the four wires into a separate crimp splice connector made for two telephone wires. Push each wire into a connector as far as it goes without stripping the insulation from the wires. These connectors strip away the insulation as you push the wires into them.
Separate the wire colours on the new phone cable that match the wire colours in use from the existing cable. Push the matching coloured wires from the new cord into the connectors holding the existing cable wires. Squeeze the crimp buttons closed with pliers. The crimp connectors release a gel around the connected wires that insulates the connection.
Cover the crimp slice connectors with cling film and electrical tape to conceal and protect them.