GSM Alarm Kit INTERVISION iMPAQ-520. GSM / GPRS is a compact wireless security and fire alarm system integrated in a motion sensor with elements of automation and a “smart home”. Equipped with a GSM / GPRS cellular communicator (dialer). Designed for the protection of such objects as an apartment, a country house, office, warehouse, cottage, garage, trading floor and more. The principle of operation is quite simple. In the protected area, motion sensors, door / window openings, smoke, temperature, gas, etc. are installed. When an intrusion is detected, the sensors transmit an alarm to the central unit over the air (without wires) or via wires if the sensors are wired. The central unit receives a signal from the sensors, turns on the siren, turns the wireless relay on and off, sends information to the monitoring station, calls the indicated phone numbers and sends SMS messages with alarm notifications.