Single-port GPRS modem emulator for lab testing
Bridge TCP polling services to physical meters via serial port without real GPRS modems.
What it is
The MIOS Modem Simulator emulates a GPRS modem connection over a single serial port (COM port), enabling you to test and develop GPRS polling services against real smart meters or RTUs without deploying physical modems. It queries the platform database for active MIOS controllers, pairs incoming TCP client connections bidirectionally with serial-port traffic, and forwards Modbus commands and replies between the GPRS service and meter. Useful for lab validation, protocol testing, and development iteration before field deployment.
Key benefits
Lab validation without hardware
Test complete GPRS polling workflows end-to-end using real meters and a single serial connection. No need to procure modems, SIM cards, or carrier contracts for development and QA cycles.
Deterministic serial protocol testing
Observe and verify Modbus RTU frame exchange (up to 262-byte messages) between polling service and meter in real-time. Simulate 60-minute modem disconnection timeouts to validate service recovery logic.
Rapid development iteration
Swap meters on the serial port and recycle the simulator without redeploying infrastructure. Load active controller configs directly from the platform database at startup.
Modbus RTU compliance
Validates CRC framing, device ID routing, and function-code handling through native serial protocol enforcement. Catches firmware/driver integration issues before production.
Capabilities
- TCP server (a configurable port) accepting simultaneous modem and modpoll connections from GPRS client services
- Queries platform database for active MIOS controllers and device serial numbers at startup
- Bidirectional data forwarding between TCP clients and physical COM port (19200 baud, 8N1)
- Modbus RTU framing with 262-byte message limit, CRC validation, and device ID routing
- Simulated 60-minute modem disconnection timeout for testing service reconnection logic
- Runtime log configuration via platform database (an internal app ID)
- Thread-safe socket and serial I/O with per-connection handlers and synchronized state
- SQL Server, Oracle, MySQL, PostgreSQL database connectivity via JDBC drivers