TX7201 Addressable Zone Monitor unit is an addressable interface module, which will integrate conventional detectors or conven- tional manual call points to addressable system. When any of the connected devices alarms are active, the unit can send the alarm ates alarm signal and displays its address. The unit can match with the conventional optical smoke detector, conventional rate of rise and manual call point etc. It has the function of checking short or open circuit of the output connection, by the End of Line Resistor (EOLR). The fault massage includes open circuit, short circuit or any removal of the detectors.