GSM call alarm is a device that will call a destination number via Siemens or Ericsson GSM phone (19200 bps RS232). It has 1 sensor input and another input – state (stanje). If state input is = 0V than the device is “active” and it monitors the sensor input. The device is deactivated when state pin is connected to Vcc (+). Sensor input is triggered by 0V.