There are two primary types of munis:
The RFM-MB1 integrates a complete RF transceiver (often based on a Semtech SX12xx series chip), a crystal oscillator, matching network, and a power amplifier. Key internal blocks include: rfm-mb1
Most modern ETFs, including likely RFM-MB1, are passively managed. They track a specific index (such as the S&P Municipal Bond Index or a customized benchmark). This passive approach keeps expense ratios low. Because bonds are traded over-the-counter (OTC) and not on a centralized exchange, the fund manager uses sampling techniques to replicate the index performance without having to buy every single bond in that index, ensuring cost-efficiency. There are two primary types of munis: The
+------------------------------------+ | B Meters GSD8-RFM | <-- Mechanical Single-Jet Water Meter +------------------------------------+ | (Optical Sensor Interface) v +------------------------------------+ | RFM-MB1 Module | <-- Electronic Overlay / Pulse Counter +------------------------------------+ | (2-Wire Polarized Bus Cable) v +------------------------------------+ | M-Bus Master / Gateway | <-- Central Network Collector +------------------------------------+ Key Technical Specifications Technical Feature Parameter / Specification Value Wired M-Bus compliant with EN 13757-2/3 standards Compatible Flow Meters B Meters GSD8-RFM series (all sizes and variations) Primary Power Supply Bus-powered line execution via the M-Bus network Backup Battery Power 3V Lithium cell (CR2032 equivalent) Autonomy (No Bus Power) Up to 1 year of independent operational lifetime Measurement Sensitivity 1-liter resolution calculation Physical Dimensions 67 mm (Diameter) x 20 mm (Height) Net Structural Weight Default Cable Length 2 meters pre-wired connection Operating Temperatures Min: +1°C to Max: +55°C environment limits Ingress Protection Class IP65 dust and moisture sealed housing Supported Baud Rates 300 bps, 2400 bps (default factory state), 9600 bps Functional Capabilities 1. Data Logging and Memory a crystal oscillator
The module is controlled via SPI commands. Primary modes: