Fire Alarm Button 2-wire conventional fire alarm system

The conventional manual call point designed for conventional fire alarm system for reporting fire or emergency condition by its button latches. The call point has one 300 ohm resistor is used on the PCB board between Zone+ and Zone- or one relay contact (NO, COM, NC ) output when the button is pressed.
The call points should be installed in a position where they will not be subjected to mechanical stresses , and where the temperature is within the operating temperature range.
Areas where there are , or are likely to be, aggressive substances should be avoided .