The **FLM-FW4W-R** is a specialized electronic component, typically categorized as a **Manual Call Station** or **Fire Alarm Box** used within professional fire detection and alarm systems (often associated with Bosch Security Systems). Below is a technical breakdown of its electronic parts and specifications. --- ### 1. General Specifications The FLM-FW4W-R is an addressable manual station designed to interface with a Local Security Network (LSN). It allows for manual triggering of fire alarms. | Feature | Description | | :--- | :--- | | **Type** | Manual Pull Station (Addressable) | | **Communication** | LSN (Local Security Network) / LSN improved | | **Wiring** | 4-wire configuration (Power + Data) | | **Material** | Die-cast aluminum/housing | | **Operation** | Dual action (usually Push In/Pull Down) | --- ### 2. Electronic Component Breakdown #### A. The LSN Bus Interface The "heart" of the device is the internal **Electronic Module (Integrated Circuit)**. Unlike conventional simple switches, this device communicates digitally with a Fire Alarm Control Panel (FACP). * **Microcontroller:** Manages the unique address of the station. * **Voltage Regulator:** Converts the LSN bus voltage (typically 15V to 33V DC) to a stable level for internal logic. #### B. Switching Mechanism The physical pull action triggers an internal **Micro-switch**. * When the lever is pulled, the switch changes state (from Open to Closed). * The electronic module detects this state change and sends a specific "Alarm" data packet to the control panel. #### C. Addressing Hardware The "FLM" (Fire Loop Module) series uses addressing to identify the exact location of the trigger. * **DIP Switches or Rotary Switches:** Located on the internal PCB to manually set the device address (001–254). * **EEPROM:** Stores the unique serial number and configuration data if electronic addressing is used. #### D. Visual Indicators (LEDs) Most versions include a status LED visible through the front or side: * **Green Blinking:** Normal operation/Polling. * **Steady Red:** Alarm activated / Acknowledged by the panel. --- ### 3. Connection Terminals The device utilizes a terminal block for 4-wire connectivity: | Terminal | Function | Description | | :--- | :--- | :--- | | **LSN a1 / b1** | Data Input | Incoming connection from the LSN loop. | | **LSN a2 / b2** | Data Output | Outgoing connection to the next device in the loop. | | **Shield/Ground** | EMI Protection | Protects the signal from electromagnetic interference. | --- ### 4. Key Electronic Features * **Short-Circuit Isolator:** The internal circuitry includes an isolator. If a short circuit occurs on the line, the device can isolate the fault to keep the rest of the loop operational. * **Low Current Consumption:** Designed to draw minimal current (typically < 1mA) to allow hundreds of devices on a single loop. * **Dual-Action Logic:** The electronics are programmed to ignore momentary vibrations, requiring a specific physical state change to prevent false positives. ---