The I/O fire alarm model FW821 provides one 24VDC output and in addition monitoring for one feedback input contact. The input line is monitored for open line faults and ground faults and the contact must be wired with an end-of-line resistor.
The output line is monitored for open line, short circuit faults, ground faults, external 24VDC power source loss and an end-of-line resistor is needed as well.
When the output is activated or the feedback is switched, the device LED will indicate the event condition by fast blinking.
A return to the normal condition will cause the event to disappear and the device LED indicator will return to the red idle condition.
The input-output module FW821 is intelligent addressable and takes one address on the Signaling Line Circuit (SLC) of the fire alarm control panel