Patent ID: 6104286
Filing Date: 2000-08-15
Classification: G08B

Abstract:
An apparatus for monitoring at least one electrical detector of the type that: 1) is AC powered; 2) has battery backup; 3) has interconnect capabilities; and 4) provides a potential difference of at least a predetermined amount on interconnect lines, so as to be responsive to a predetermined ambient condition at a given location, said apparatus comprising:first circuitry for connecting at least a substantial fraction of the potential difference to a first relay included in said first circuitry of the apparatus so as to provide a predetermined first indication; andsecond circuitry responsive to a potentially detrimental electrical condition in the apparatus that is outside a predetermined range, said electrical condition thus representing a potential detriment to the optimum performance of the apparatus, so as to cause said second circuitry to thereby provide a predetermined indication of the detrimental electrical condition;wherein a smoke detector loop from a central alarm system panel is monitored by the panel to distinguish an alarm state from a trouble state, said alarm state being present when said electrical detector senses said electrical condition, and said trouble state being present when it is detected that the loop is open or has a high impedance;wherein the smoke detector loop includes a current source generated by and monitored by the panel such that current on the loop is limited by the panel and by an end of the line resistor external to the panel, the resistor limiting the current by closing the end of the smoke detector loop; and wherein the central alarm system panel responds by:a) in a no alarm state and a no trouble, measuring a defined current range that circulates through the loop; andb) in the alarm state, measuring a marked increase in current flow through the loop, and thereby turning on an audible or visual indicator to alert the alarm user; andc) in the trouble state, measuring no current circulating in the loop because the loop has been affected so as to produce a high impedance, thereby turning on an audible or visual indicator that is different from the indicator used in the alarm state.