Fire detection systems combine three parts.
 
Input Devices : They are sensors, detectors , buttons and detect incoming alerts elements.
Evaluation Unit : It is the fire detection panels that collect input devices signals, make the necessary notifications and control output units.
Out put devices : They are devices such as sound and light warning devices, that are allowing to control other tools, telephone news transmission equipment and announcements control devices.
 
     Fire detection systems are classified according to the assessment units technology.
 
1.Conventional Systems
 
     All input elements , which are used in this system (detector, buttons, etc..), are "Two-position" devices. These elements will be in "normal" position until they feel a warning will. It will pass "alarm" position after perception of warning.
 
     Conventional panel can not evaluate one by one each input elements warnings, when on a line any input element passed the alarm condition, all the lines would pass alarm condition and it will be difficult to find where the alarm is comming from, so the elements to be grouped in "zone" , and each zone is connected to the panel seperately. When any detector is alarming, we will be able to see on the panel in which zone's detector is alarming. In practice, It is usefull not exceeds the average of 20 input devices.in a zone , depending on the architecture of the building. 
 
2.Addressed Systems
 
     All elements used in these systems are capable of communicate with the panel. During this communication elements are introduced themselves with a special coding "addressed". The panel receives information about individual communications status of all the elements. In this way, when the panel warnning fire you can determine the exact location of the fire response and it will be faster to control fire. With adressed system during the wiring cross zoning is not necessary. If zoning is requested, It is possible to make with the panel program. The number of elements per line can be put into according to the brand. (For example Honeywell is 99 detectors, and 99 modules in the panel) Due to these types of addressing panels are easy to identify the fault location as well. With this panel , if necessary, conventional elements can be connected with the specific addressing modules. This type of panel is being used anymore.
 
3.Analogue Addressed Systems
 
     In systems with conventional systems’ and also addressed systems’ detectors are reported only normal or alarm conditions in the panel. With the development of technology during the comminication between detectors and panels , detectors are   measured and reported smoke / heat quantities with address to the panel. Panel is measured value for each detector, compared and decided that it is exceeded the danger limit or not. Because of these characteristics, analogue addressed systems detectors are also used in terms of sensors.
 
     It is possible to define a threshold level for each detector separately in this systems. In this way, in order to avoid false alarms; in a more dusty environment the lower sensitivity, such as information processing clean room areas with a high sensitivity is selected to detect fires more quickly. Moreover, at the time the building was empty, it is possible to increase system accuracy It is also possible to use pre-alarm warning before measured the level of smoke .
 
     All the smoke detectors are being dirty because of the dust in the atmosphere so periodic maintenance is an requirementto prevent false alarms. In the building that include many detectors has got problems with periodic maintenance. The panel is measured values of dirty of the detectors and It is possible to get a maintenance alert . It is preferable to clean the dirty detectors instead of cleaning all detectors.
 
4.Wireless Systems
 
     Such systems the communication between the panel and detectors are provided with a small transmitter.Batteries must be used as the power source of detectors.