Remote control system for inaccessible telecommunications appts. - uses reversible DC motor, controlled frequency transformer and flip flop circuit

摘要

The remote-control system is used for regulating an inaccessible telecommunications unit via the terminal station, e.g. for an equaliser incorporated in an underwater telephone line. It uses a reversible Dc motor (M) and a transformer supplied with a control frequency (F) having two secondaries (51, 52) connected across the motor terminals (31, 32) via respective rectifier and filter circuits (D1, C1, D2, C2). A flip-flop circuit (B) has its control input (C) connected to the motor terminals (B1, B2), for supplying one of two potentials to the second motor terminal (B2), for supplying current to the motor in one sense or the other. Means (54, 55) are provided for obtaining a control signal in dependance on the state of the flip-flop circuit, indicating the required direction of rotation of the motor.