2-Wire Heat Detectors

2-Wire heat and smoke circuits use a pair of wires for both power and signalling functions. On 2-wire circuits, the detectors are wired in parallel along a single path with an EOL resistor at the end of the circuit. When any detector goes into alarm, the circuit is brought to a near short. The panel senses the change and goes into alarm.

2-Wire systems can often show a cost saving on installation due to the reduction in cabling.