The L5100 has a built-in siren that sounds at 85 and 110 decibels.
The L5100 is the epitome of a self-contained security system. Not only is it a control/keypad all-in-one, but it has such a loud sounding siren that it doesn't require the installation of any additional Honeywell sirens. The L5100's siren is automatically enabled through default system programming, and the volume level of the siren is fully adjustable. To change the decibel level of the siren, click "Sounder". "Burglary Alarm Sound" will be displayed. Select "Yes" for the 110 dB siren. Select "No" for the 85 dB siren (has a higher pitch).