The **ALR-024-R/BL** is a specialized electronic component primarily used in fire alarm systems and emergency signaling. It is an **Addressable Remote Indicator (LED)** designed to provide visual confirmation of an activated detector, typically used when a detector is hidden (e.g., inside a ceiling void or a locked room). Below is a detailed breakdown of its electronic specifications and features. ### 1. Technical Specifications | Feature | Specification | | :--- | :--- | | **Operating Voltage** | 17V – 41V DC | | **Quiescent Current** | ~ 250 µA | | **Alarm Current** | ~ 2 mA (LED On) | | **LED Color** | Red (High Intensity) | | **Color of Housing** | White / Blue (BL denotes base/branding variation) | | **IP Rating** | IP42 (Indoor use) | | **Communication Protocol** | ESP (Enhanced Systems Protocol) | --- ### 2. Key Electronic Components & Functionality #### A. The Addressable Module Unlike standard conventional LEDs that simply turn on when power is applied, the **ALR-024** contains an internal integrated circuit (IC) that communicates with the Fire Alarm Control Panel (FACP). * **Unique Addressing:** It can be assigned a specific address on the signaling line circuit (SLC). * **Remote Activation:** The panel can trigger the LED independently of the detector it is monitoring, allowing for complex cause-and-effect programming. #### B. High-Intensity LED The "R" in the part number stands for **Red**. The device uses a low-current, high-efficiency LED. It is designed to be visible even in bright ambient light conditions to ensure rapid location of the fire source. #### C. Loop Powered Design The device draws its power directly from the fire alarm loop. It does not require a separate 24V power supply, which simplifies wiring. * **Terminal Connections:** Usually features simple screw terminals for `Loop (+)` and `Loop (-)`. --- ### 3. Application Use-Case * **Void Detection:** If a smoke detector is placed above a false ceiling, the ALR-024 is mounted on the ceiling tile directly below so fire wardens know which hidden sensor triggered. * **Secure Rooms:** Placed outside a locked server room or storage area to indicate an alarm inside without needing to enter the room. --- ### 4. Wiring Overview The ALR-024 is typically wired in parallel to the loop: ```mermaid [Panel] ---- (+) ---- [Detector] ---- (+) ---- [ALR-024] ---- (-) ---- [Detector] ---- (-) ---- [ALR-024] ``` ---