Twisted Pair

The wires in twisted pair cabling are twisted together in pairs. Each pair consists of a wire used for the +ve data signal and a wire used for the -ve data signal. Any noise that appears on 1 wire of the pair will also occur on the other wire. Because the wires are opposite polarities, they are 180 degrees out of phase (180 degrees - phasor definition of opposite polarity). When the noise appears on both wires, it cancels or nulls itself out at the receiving end. Twisted pair cables are most effectively used in systems that use a balanced line method of transmission: polar line coding (Manchester Encoding) as opposed to unipolar line coding (TTL logic).