| CPC G08B 17/107 (2013.01) [G08B 29/043 (2013.01)] | 19 Claims | 

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               1. A fire sensing device, comprising: 
            a first transmitter light-emitting diode (LED) configured to emit a first light; 
                a second transmitter LED configured to emit a second light; 
                a controller configured to command the first transmitter LED to cease emitting the first light and the second transmitter LED to start emitting the second light; and 
                a photodiode configured to: 
                detect a scatter level of the first light; and 
                  detect a scatter level of the second light; 
                wherein the controller is configured to: 
              transmit the detected scatter level of the first light and the detected scatter level of the second light to a monitoring device; 
                  receive a command from the monitoring device; and 
                  command the second transmitter LED to cease emitting the second light responsive to the command from the monitoring device. 
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