D, according to the alarm range points: point control alarm, line control alarm, surface control alarm and space control alarm.
C, according to the detection of electrical signal transmission channel classification: can be divided into wired alarm and wireless alarm.
B, according to the work of the detector classification: can be divided into active and passive alarm. Active detectors are responsible for some form of energy, such as infrared, ultrasonic, and microwave, in the field of vigilance. Passive detectors do not need to send any form of energy to the site of the precaution during their vigilance, but rather detect the energy from some form of energy, such as infrared, vibration, etc., from the target being detected.
A, according to the type of sensor: magnetic switch alarm, vibration alarm, sound alarm, ultrasonic alarm, electric field alarm, microwave alarm, infrared alarm, laser alarm and video motion alarm. Install the two sensors in a detector, called a dual-technology alarm.
