Abstract: A mechanism for switching from independent to synchronous, or vice versa an operational circuit for supplying power to an electric dust collector (Slave) when an electric power tool (Master) is operated. In independent mode, power is supplied to both the electric power tool and the electric dust collector at all times. In synchronous mode, power is supplied to the electric power tool at all times. The current drawn by the electric power tool is directed through a coil of an electromagnetic relay. When the electric power tool is operated, the current flowing through the coil of the electromechanical relay creates a magnetic field which operates the contact of the electromechanical relay. The contact of the electromagnetic relay directs power to an electric dust collector.