Conventional Detectors
Series 65 Ionisation Smoke Detector 
Air in the dual sensing chambers is irradiated to produce ions that travel to the positive and negative electrodes, creating a current flow. As smoke enters the outer chamber, the flow drops and the voltage increases. The detector will then enter the alarm state and the indicator LED lights up.
An intergrating ionisation detector, suitable for use in areas where transient high levels of smoke may be expected, is also available.
Series 65 Optical Smoke Detector
The optical smoke detector uses an internal pulsing LED and a photo-diode at an obtuse angle. In the event of smoke entering the chamber, the light pulse from the LED will be scattered and registered by the photo-diode. The detector will then enter the alarm state and the indicator LED lights up.
Series 65 Ionisation Heat Detector
The heat detector operates by using a matched pair of thermistors to sense heat. One thermistor is exposed to the ambient temperature, the other is sealed. In normal conditions, the two thermistors register similar temperatures, but, on the development of a fire, the temperature recorded by the exposed thermistor will increase rapidly, resulting in an imbalance of the thermistors and causing the detector to change to the alarm state.
1R, BR and CR are Rate of Rise detectors, designed to detect a fire as the temperature increases, but they also have a fixed upper limit at which the detector will go into alarm if the rate of temperature increase has been too slow to trigger the detector earlier.
CS detector is a fixed heat detector which only changes to the alarm state at a preset temperature.
Series 65 Base
The bases have been designed to enable detectors to be plugged in without any need for force and have a "one way only" fit.
The standard base contains no electronic parts which could be damaged during installation.
Series 65 Replay Bases
Several types of relay base are available: an auxiliary relay base and two types of EOL (End-of-Line) relay bases designed for circuits with supply voltages of between 9 and 18V DC and 16 and 33V DC.
