Abstract: A telephone activated power controller comprised of an electrical power inlet and a number of power outlets for supplying power to the devices of a computer or other system. A detection circuit detects telephone rings and off-hook conditions and powers up the system. A remote control circuit allows the computer to keep the power on after hang-up or manual power-off. A status sensor circuit tells the computer if the device has been turned on manually or remotely. An inhibit circuit prevents the device from responding to a telephone ring or off-hook condition if it is engaged. The controller also has a surge protection circuit to prevent large voltages or current from reaching the power outlets.

Abstract: A circuit containing a pair of spaced leads and first, second and third current paths across the leads. The first path defines a first stage containing a first zener diode in series with a first resistor. A second zener diode can be placed in parallel across the first resistor to prevent excessive buildup of voltage across the first resistor. The second path defines a second stage containing a varistor which acts to relieve the first stage with a higher power dissipation but at a slower reaction time. The third path defines a third stage containing a gas discharge tube in series with a second resistor. A varistor is in parallel with the second resistor of the third stage to limit the voltage across the second resistor due to impulse current. The circuit combine the zener diodes, the varistor and the gas discharge tube in a manner to ensure rapid response and high energy dissipation to incoming transient impulses.