Abstract: A system is disclosed for transmitting a sensed temperature from a transmitter to a remote receiver over a modulated carrier through the atmosphere. The transmitter and the receiver are battery powered and include timing circuitry having low power consumption. The transmitter and the receiver are both cyclically turned on for a relatively short period and off for a relative long period with the receiver's on cycle being synchronized with the occurrence of the transmission of the modulated carrier. The receiver further employs techniques to minimize the effect of noise on the reception of the transmitted data which can occur from extraneous signal sources broadcasting in the same frequency band or from environmental noise.

Abstract: An automatic centralized monitoring system capable of monitoring various sensors in a plurality of premises with rapidity; this is accomplished by combining the premises into a plurality of groups; the central station is provided with as many computer-controlled line drivers as there are groups; all of the line drivers are able to simultaneously read the sensors in one premise of each group. The sensor readings are multiplexed and returned to the computer which interprets the readings.

Abstract: A photoelectric smoke sensing and alarming device capable of discriminating the smoke generated by a fire from other smokes such as cigarette smoke. The device has a chamber into which the smoke is introduced. The chamber accommodates a light-emitting element adapted to emit a light beam in the form of pulses and a light-receiving element sensitive to the scattering of light due to the presence of the smoke in the chamber. The output from the light-receiving element is delivered to an amplifier which in turn delivers an output to a gate circuit having a level comparator adapted to compare the level of the output from the amplifier with a reference sensing level. Means are provided for actuating an alarming circuit only when more than two successive pulses of level exceeding the reference sensing level are generated.

Abstract: An audiovisual signaling device including an auditory signaling means, an inductor for energizing the signaling device, and a circuit interruptor in series circuit with the inductor. A flashtube is electrically connected to the inductor and interruptor, and the inductor acts as an electromagnet when a voltage is impressed across the inductor and interruptor. The series circuit is intermittently interrupted by the interruptor, and the flashtube is actuated in response to the decaying magnetic field of the inductor when the circuit is thus interrupted.

Abstract: A light emitting diode has a metal casing connected to the cathode electrode thereof to protect the light emitting diode from the ambient conditions. Detector circuitry is provided for detecting touch operation by an operator to the metal casing of the light emitting diode. A driver is responsive to the output of the detector circuitry for enabling the light emitting diode when the touch operation is effected to the metal casing of the light emitting diode.