# Fire alarm interface * The Hub includes a **FIRE IN** input that can be connected to an isolated relay driven by a fire alarm system. Do not connect this input to a power supply * Configure the sense of the relay (normally open or normally closed) using the slide switch on the Hub (a red indicator lights up when the fire condition is indicated). A loop resistance greater than 500 kOhms will be interpreted as Open and a loop resistance less than 500 Ohms will be interpreted as Closed * Use a shielded cable and connect the shield to earth using the labeled earth post inside the enclosure * When the FAI is used, you can configure each lock to unlock in response to the fire condition * For each lock, set the corresponding fire override slide switch to on. Note that you must set the power-to-lock/power-to-open switch correctly to ensure that the lock will unlock during a fire condition * When using the FAI feature, the installation must be tested and approved by the relevant fire authority to ensure that the behavior results in a system that is safe * For any power-to-open locks, do not rely on this feature for safety, as failures elsewhere in the system can result in power loss to the lock * This feature is not a substitute for mechanical overrides or break-glass disconnects at the exit door to allow for safe exit from the building in the event of an emergency --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.accessia.com/hardware/ai-security-hub-hub-v1/inputs-and-outputs/fire-alarm-interface.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.