A term used for a popular style of network cabling adapted from telephone cable. Telephone companies commonly run twisted pairs of copper wires to each customer household. The pairs consist of two insulated copper wires twisted over their length into a spiral or braided pattern. There may be multiple “pairs” of wire within a single cable. The benefit of twisting the pairs together is that it will not only reduce crosstalk or electromagnetic induction between pairs of wires, but will also make them less susceptible to outside interference. When current (electricity) passes through any wire a (usually very) small magnetic field develops around it. If other wires are in close proximity, the electrical current from one wire may be “induced” into an adjacent wire. When they are twisted around each other, the magnetic field is randomized to an extent that this induction is greatly reduced. Further, this randomization of the wire’s orientation makes it much more difficult for stray EMI to become inducted into the wire.
In order to send high speed (frequency) data over distances, wire must generally be some variety of twisted pair. There are many different variations on this theme for transmitting different types of data. Sometimes shielded wire is used, other times not. The number of twists per foot of cable will also vary depending upon the desired application. The standard for Category 5 networking cable, for example, states the twisted pairs must have at least 8 twists per foot.