Johnson Controls tyco iSTAR Ultra, Installation And Configuration Manual, Page: 91 / 118

FAI Connections
iSTAR Ultra Installation and Configuration Guide 5–25
Figure 5-21: FAI without Latch
FAI with Latch followed by Key Unlatch
If the Latch Enable switch (SW30) is on and the F input goes true the selected relays will
activate and stay that way until an Unlatch is given.
1. J84 is in its normal state with F (NC) closed and K (NO) open.
2. F opens signaling a Fire Alarm and all enabled relays are activated by the Relay Drive, as
in FAI without Latch.
3. F input closes indicating the Fire Alarm has been reset, BUT the relays stay activated
(Latched).
4. Sometime later, probably after investigation, K closes and deactivates the relays. This
input is named K because this input is usually a Key operated switch.
5. When K opens again, everything is back to normal.