Abstract: There is disclosed an interlock between a wood working tool and a dust control system in which a standard pressure switch, which can be activated by negative or positive pressure, is located in the dust collector duct which extends to the wood working tool. The switch is electrically connected to the magnetic starter for the wood working tool. The pressure switch responses to a sensed condition of subatmospheric pressure in the dust collector duct to provide power to the woodworking tool, thus insuring that the dust collector system must be functioning to permit operation of the wood working tool. When the dust collector duct becomes blocked or the dust collector fails to function for any reason, the pressure in the duct rises, automatically activating the interlock and interrupting the power supply to the woodworking tool.