I recently upgraded my home internet setup to a Teltonika RUTX50 dual SIM card router and wanted to share a detailed guide on integrating it with Home Assistant for GSM signal monitoring. This setup helps maintain stable connections, especially when dealing with ISP-induced tower changes or power outages. Here’s how I achieved it:**Router Setup:**1. Custom Modbus Register Block: Follow the instructions outlined in the Teltonika Wiki to set up a custom Modbus register block. This allows the router to pass detailed GSM information to Home Assistant.2. Script Creation: I created a script named /bin/extramodbus to continuously gather GSM data using gsmctl and format it for Modbus. The script runs every 8 seconds to ensure real-time updates.3. Modbus Configuration: Configure the Modbus settings in the router’s UI to ensure data is correctly transmitted to Home Assistant.**Home Assistant Integration:**1. Configuration YAML: Include the Modbus and template integrations in your configuration.yaml to parse the incoming data.2. Sensors Setup: Define sensors for various GSM metrics like signal strength (RSRQ, RSRP, RSSI), SINR, and cell IDs. These sensors provide a comprehensive view of your GSM connection health.Example Setup:- Modbus.yaml: Configure the Teltonika RUTOS as a Modbus TCP slave and define sensors for GSM data.- Templates.yaml: Use template sensors to parse and display the raw Modbus data in a user-friendly format.This integration has been invaluable for monitoring my connection stability and quickly identifying issues. I’d love to hear if others have implemented similar setups or have suggestions for improvement. Feel free to ask questions or share your experiences below!