What triggers the start and end of siren and lights?
• For an event to be decoded by LAWS, NOAA Weather Radio transmits a radio frequency signal on the VHF-FM broadcast band following NOAA’s “SAME” (Specific Area Message Encoding) protocol. This is a digitally encoded transmission, which provides this encoding through Frequency Shift Keying (FSK), more specifically Audio Frequency Shift Keying (AFSK). This transmission contains digital data, and includes information related to the type and duration of the event as well as the geographical location affected. In turn, upon receiving this signal, LAWS circuitry decodes this data, and if appropriate initiates the relevant warning process which includes control of the speakers and the lights.
