Twisted-pair cable such as Cat5e, Cat6 or Cat7 is a type of cabling that is used for phone systems and most modern Ethernet networks. A pair of wires forms a circuit in order to transmit data. The pairs are twisted to provide protection against cross-talk, which is the noise generated by adjacent pairs. When electrical current flows through a wire, it creates a magnetic field around the wire. When two wires in an electrical circuit are placed close together, their magnetic fields are the exact opposite of each other. Thus, the two magnetic fields cancel each other out. They also cancel out any outside magnetic fields. Twisting the wires can enhance this cancellation effect. Using cancellation together with twisting the wires, cable designers can effectively provide self-shielding for wire pairs within the network media.