Security device and security system determining if the user can hear an audible alarm

摘要

This security device includes a control portion determining whether or not a user can hear an alarm sound for informing the user of an abnormality when the abnormality occurs and informing the user of the abnormality by generating the alarm sound, or illuminating or blinking a light in a house of the user, depending on determination whether or not the user can hear the alarm sound.