It is common knowledge that smoke chambers are gradually filled with dust. According tomaintenance provisions, the frequency of detector cleaning shall be set by the manufacturer (usually aperiod of 6 months). Accumulated in the smoke chamber suspensions of dust under mechanical pressureor due to strong through holes cause false actuations. This is most pronounced from the second to fourthto fifth years of operation. And then optopara generally loses the ability to respond to something.Detectors should be cleaned with the specified manufacturer periodicity, and then their operabilityshould be checked. It was much easier for technicians to measure the dust level of each detector directlyon the instrument. Such an opportunity is available only in hell-and-heart-analog systems. Thus, theoperational cause of false operations can be eliminated when using address-analog systems. Thatexplained the popularity of those systems abroad.