Practices in telephone transmission maintenance work: Telephone circuit unbalances

D. I. Cone: To the engineers and maintenance people of the operating telephone systems these advances in the means for maintaining the circuits are very gratifying. There are two major reasons for their need: First, in order to employ economically the communication plant, as many types of service as possible are put on the wires. Balancing the circuits is one means employed to separate one channel of communication from another. Second: The growth of power circuits and their inductive fields has been so great that communication circuits, which originally had the field very much to themselves, are now forced to exist in the presence of large inductive and conductive fields. Since the same people want both power and communication service it is impossible altogether to prevent that. The original telephone circuits would be wholly inoperative under present-day conditions but for the advances made, on the one hand, by the method of balancing the communication circuits, and on the other hand, by measures taken in the supply circuits to limit their fields of influence.