1. In a hybrid set, hybrid coil, or resistance hybrid, a circuit used to match, i.e., to balance, the impedance of a uniform transmission line, i.e., twisted metallic pair, over a selected range of frequencies. Note: A balancing network is required to ensure isolation between the two ports of the four-wire side of the hybrid. 2. A device used between a balanced device or line and an unbalanced device or line for the purpose of transforming from balanced to unbalanced or from unbalanced to balanced.