Remotely activated switching apparatus

Abstract

Apparatus for disconnecting and reconnecting equipment to a telephone line in response to a signal sent over the telephone line. The apparatus includes a voltage threshold circuit, a voltage regulator circuit and a switching and timing circuit. The switching and timing circuit includes a first energy storage capacitor and a first discharge circuit. The switching and timing circuit further includes a second energy storage capacitor and a second discharge circuit and further includes a third energy storage capacitor and timing resistor. The first discharge circuit includes a first semiconductor switching device and a relay coil of a latching relay. The second discharge circuit includes a second semiconductor switching device and a second relay coil of the latching relay. When a signal is sent over the telephone line which exceeds the threshold level, it is regulated by the voltage regulator and charges up the first, second and third storage capacitors in an order such that the third capacitor charges first, the second capacitor next and the first capacitor last. Once the signal disappears from the telephone line, the first storage capacitor discharges into the first discharge circuit, thereby placing the switch into a first switching state and disconnecting the customer equipment. In this state, a test circuit, for example, may be connected to the telephone line to enable the central office to test the telephone line for faults. After a predetermined time delay determined by the discharge of the third energy storage capacitor into the timing resistor, the second discharge circuit is activated by a voltage differential between the second and third storage capacitors whereby the switch is switched from the first state back to the second state, thereby reconnecting the customer equipment, for example, a telephone, back to the telephone line.