Whether you are setting up a new phone system, adding a line, or simply repairing a line, it is helpful to know the nuts and bolts of telephone wiring.
Line cord. This flat, often gray cord is the one that plugs into a jack at one end and into a phone at the other. While you should never splice line cords, you can “two-line” cords together by using a small coupling.
Two-line means basically running a second or separate phone line into a home where there already is a connection; this is handy for “teen” phones or when creating a home office with a fax line. It is important to remember that telephones work on very low voltage, so if you plan on positioning your telephone more than 25 feet from an existing jack, it is better to run a station wire to a closer location and install a new jack there.
Handset cord. The tightly coiled cord that connects the handset to the base of a landed phone is called, appropriately, a handset cord. If you are replacing one, be sure to buy the right type for your phone as different phones require different handset cords.
Station wire. This multi-conductor wire connects to the network interface jack, where the wires from your telephone service provider come into the house. It should never be run outdoors without being housed in a conduit or, better yet, replaced by a solid-core version made specifically for outdoor use.
Station wire comes in two-pair wire (four conductors), three-pair wire (six conductors), and four-pair wire (eight conductors). Each wire is insulated with a distinctively colored sheathing. One pair of wires is for telephone service; the others are for backup if the basic-service wires malfunction for any reason, for grounding, or for adding more phone lines in the future.
Wire junctions. The meeting place for multiple phone lines, wire junctions come in several options. There is the 42A block, a 4–line wire junction, or you could devise your own by using a standard junction box and wire nuts.
Modular jacks. A phone jack connects the line cord to the station wire. There are several options to choose from, including single, double, and combination jacks in flush-mounted and surface-mounted styles.
Flush-mounted jacks are usually used in new construction because they can be fastened directly to wall studs before drywall or other types of wall covering are installed. If you are remodeling, you can simply insert a special bracket into an opening in a wall and then screw the jack’s cover plate to the bracket. The simplest method of all is to affix surface-mounted jacks onto baseboards with short screws.
To add another line to a jack, use a dual-outlet adapter; a triplex adapter accommodates two other lines.
How many jacks do you need? With our modern-day demand for easily accessible telephones, fax machines, computers, security systems, and satellite entertainment systems, it is not uncommon for builders to install 15 to 20 jacks in a new home. At the very least, a home should have one jack per room and two or more in those rooms that serve as entertainment centers, home offices, and the like.