Abstract: A novel circuit and method are described for monitoring a telephone line of a switched telephone system. The line monitoring circuit is interposed in the telephone system between the local subscriber-line from the central office and the on-premise continuation of that line at the subscriber's location. The line monitoring circuit has component circuitry for sensing both line-to-ground faults and extraneous AC voltages of a predetermined magnitude and frequency. Upon sensing a line-to-ground fault or an extraneous AC voltage of the predetermined magnitude and frequency, a control signal is transmitted to a relay control element which operates to disconnect the on-premise portion of the line from the portion of the line which extends from the subscriber's premise to the central office of the utility company. Visual indicators are also provided with the circuit. The indicators show whether a line-to-ground fault or an extraneous AC voltage fault has caused the relay to operate.

Abstract: An improved ignition device wherein a spark plug is provided with a torch chamber surrounding the spark gap. A first mixture of fuel-rich fuel and air is supplied to the torch chamber where it is ignited by a spark and propelled as a jet of burning fuel into the combustion zone of a cylinder of an internal combustion engine. The burning fuel from the torch chamber provides suitable ignition of a relatively lean second mixture of fuel and air in the combustion chamber which mixture is leaner than would otherwise be suitably ignited with a spark from a conventional spark plug. A porous plug in the fuel line acts as a one-way valve by allowing liquid fuel to pass by capillary and/or seepage action while resisting backflow caused by periodic high pressures within the combustion chamber. A cooling and heat-shielding system protects the fuel supply system against excessive heat absorption which would tend to prematurely vaporize the fuel and interfere with the valving apparatus.