A line cord goes between the base of a telephone and a phone jack. It's called a line cord, because it provides access to the phone line so you can make and receive calls. Most of the line cords below are described by the number of conductors they have. A conductor is a narrow strip of stranded or solid copper wire that runs through flexible plastic insulation. A common electrical circuit (whether used by a phone, bicycle horn or dishwasher) is composed of a pair of wires. One pair equals two conductors, working together. Traditionally, a phone required one pair per phone line (i.e., a phone number). Modern electronic or digital "office" phones can access many lines with just one pair. So, how many pairs or conductors do you need?
Most phones use four-conductor line cords. Unless you know your phone uses more or fewer, get four.
If you need a cord for an HP fax machine or VoIP, get two.
Some phones and telecom gadgets use six or eight conductors (three or four pairs), so order the right thing.
Some old phone guys call a line cord a "base cord" or a "mounting cord." Standard lengths are 7, 14, and 25 feet, but other sizes are available.
Line cords are not used just for phones. They are used for lots of telecom equipment, including faxes, modems (remember them?) answering machines (remember them?) credit card terminals, patch panels, Caller ID displays, alarm systems, chimes, strobes, and more.
IMPORTANT NOTE: If you have a self-contained "consumer" 2-line phone, we do not recommend the use of cords longer than 7 feet, because of the strong possibility of getting crosstalk (bleeding of a conversation or noise from one line to another). If you need a long cord, use our special anti-crosstalk cord, which has twisted pair construction, rather than four parallel wires used in the extension cords.
Some multi-line "system" phones that have separate wire pairs for "voice" and "data" also need twisted-pair cords.