Abstract: A gas detector and method of operating the gas detector that includes a carbon monoxide sensor and a processor. The carbon monoxide sensor senses an environmental concentration of carbon monoxide and provides the sensed value to the processor. Upon receiving the value of the carbon monoxide level (COppm), the processor determines an alarm threshold level based upon the COppm level. Once the alarm threshold level is determined, the processor calculates the COHb percentage for the current COppm reading based upon a derived, fixed point equation. The processor activates an audible/visual indicator when the sensed COHb percentage exceeds the alarm threshold.

Abstract: A method of testing the operational status of remotely distributed hazardous condition detectors is provided. The method utilizes the detector's self-test button to initiate a detector self-test. Once the self-test is complete, the detector's alarm is silenced and a remote self-test signal is sent to the interconnected remote hazardous condition detectors. The remote detectors, on receipt of this signal, will initiate a self-test of their own as if a user had depressed their test button. The user, with the local detector's alarm now silenced, is better able to hear the remotely interconnected detector's alarm. To verify that the remote self-test signal is received, thus verifying the operational integrity of the communications link, the remote detectors may sound an alarm pattern indicative of the receipt of the signal before initiating their self-test.

Abstract: A circuit board test apparatus includes an interchangeable interface board adapted for use with a particular type of circuit board to be tested, a receiver board with which said interface board engages, a back plane board located generally parallel to said receiver board and containing analog and digital buses, and a plurality of analog and digital interface and controller boards mounted generally perpendicular to said receiver and said back plane boards and electrically connected thereto. The test apparatus also includes vacuum apparatus for drawing the circuit board to be tested into engagement with the interchangeable interface board and further includes several embodiments of means for directing a stream of ionized air across the circuit board to be tested to eliminate static electrical charges therefrom.