Conventional detectors are simply on/off devices - if there is
no smoke or heat they do nothing. If there is a certain, pre-set
level of smoke or heat, they switch into the 'Alarm' state. Devices
are connected to one circuit, known as a zone, and each circuit is
connected to a control panel. If a conventional detector goes into
alarm, the control panel will be able to identify which zone has
gone into alarm, but not where exactly the fire has broken out.
For more information of conventional fire systems, visit the Questions pages.