The **S4-DB6-R** is a specific model of an addressable detector base, typically used in fire alarm systems (most notably by **Siemens**). It is designed to interface between the physical wiring of a building's fire alarm system and a plug-in smoke, heat, or multi-sensor detector. ### Technical Specifications The following table outlines the key electrical and physical characteristics of the S4-DB6-R base: | Parameter | Specification | | :--- | :--- | | **Manufacturer** | Siemens (Cerberus PYROTRONICS / Faraday) | | **Base Diameter** | 6 Inches | | **Wiring Style** | 2-Wire (Addressable) | | **Connection Type** | Screw Terminals (with wire clamping) | | **Compatibility** | S-Series Detectors (S-121, S-135, etc.) | | **Material** | Flame-retardant Polycarbonate | --- ### Key Electronic & Structural Parts #### 1. Terminal Block Assembly The core electronic interface consists of metal screw terminals. These are designed to handle: * **Loop In/Out:** Facilitates the continuous communication loop from the Fire Alarm Control Panel (FACP). * **Remote LED Support:** Some versions include a terminal to drive a remote indicator lamp if the detector is hidden (e.g., above a false ceiling). #### 2. Shorting Spring (Continuity Link) One of the most critical electronic features is the **automatic shorting spring**. * **Function:** It maintains loop continuity when the detector head is removed. * **Benefit:** This allows installers to test the wiring for "opens" or "shorts" without having the expensive detector heads installed. Once the head is twisted in, the spring is pushed aside, and the detector takes over the circuit. #### 3. Locking Mechanism While mechanical, this part protects the electronics. It consists of a small plastic break-out tab that, when activated, prevents the detector head from being removed without a specific tool, protecting against tampering. #### 4. Addressability Logic It is important to note that the S4-DB6-R is a **passive base**. The "intelligence" or digital address is located in the **Detector Head** itself, not the base. The base simply provides the mechanical and electrical bridge to the SLC (Signaling Line Circuit). --- ### Wiring Configuration The base uses a specific numerical marking for terminals to ensure correct polarity: 1. **Terminal 1:** Positive (+) Line In/Out. 2. **Terminal 2:** Negative (-) Line In/Out. 3. **Terminal 3:** Optional Remote LED (Output). 4. **Terminal 4:** Shield/Earth Ground (to prevent electromagnetic interference).