You have to decide whether to install or do install an alarm, because you've already been burglarized or you are afraid of the rise of insecurity.
The figures are eloquent : there is a robbery every 90 seconds in France !
Then it may be time for you to equip you with an alarm.Each protective device to its own characteristics.
Today there are two exit alarm system:the alarms wired and the tears of wireless so-called radio for radio frequency.
The more on of alarm remains on the alarm wire.The sensors are linked to an alarm central, by a thread.If the connection between the sensor and the central unit is interrupted while the alarm triggers an audible or visual signal or both.
The signal between the alarm central may not be disturbed.
The disadvantage of the alarm is wired on the installation which must be thought before the renovation or construction in order to pull the cable specially for alarm.A hardwired alarm system will have a quick installation superior workforce because it should be asked of the trays and pull the cables in the case of the renovation.
Today the market is overrun by the wireless alarms which works on the radio waves of the band LPD433 for LOW POWER DEVICE or devices to low-power.The frequency of 422 MHz, distributed over 69 channels of 433.50 MHz to 434,70 MHz in steps of 25 MHz.
The effective radiated power is 10 mW (milliwatt).This frequency is used for wireless applications,remote controls, car ,portal,porters, wireless video,wireless alarms,toys...
The alarms without wires are very sensitive to obstacles,wave reflection,refraction,diffraction and interference radio,to the effect of FARADAY.