Balanced line

In telecommunication, a balanced line is a transmission line consisting of two conductors in the presence of ground, capable of being operated in such a way that when the voltages of the two conductors at all transverse planes are equal in magnitude and opposite in polarity with respect to ground, the currents in the two conductors are equal in magnitude and opposite in direction.

Note: A balanced line may be operated in an unbalanced condition. Synonym balanced signal pair.

Source: from Federal Standard 1037C and from MIL-STD-188