Unbalanced line is an electrical cable in which the potential of the signal-carrying conductor is above ground while the return-path conductor is at ground potential. The two conductors thus have different electrical characteristics. This is different from a balanced line, in which both conductors carry a signal and have potentials that are equal in magnitude but 180 degrees out of phase.
In computer networking, an example of an unbalanced line is coaxial cabling, in which the electrical signal is carried solely by the central conductor while the ground path (the internal wire-braid or mesh shielding inside the cable jacket, which is connected to the earth at one termination point of the cable) provides the unbalanced signal return path. An example of a balanced line is twisted-pair cabling, which comes in the shielded twisted-pair (STP) or unshielded twisted-pair (UTP) variety. Because of its electrical characteristics, unbalanced coaxial cabling is more susceptible to electromagnetic interference (EMI) than balanced STP cabling, but coaxial cabling is capable of higher transmission rates over longer distances.
Graphic U-1. The return-path conductor of the unbalanced line is at ground potential. The return-path conductor of the balanced line carries a signal.