ArduinoModbus : Modbus RTU Server class
Start the Modbus RTU server with the specified parameters.
ModbusRTUServer.begin(id, baudrate);
ModbusRTUServer.begin(id, baudrate, config);
id - (slave) id of the server
baudrate - Baud rate to use for serial
config - Config to use for serial (see Serial.begin(...) for more info.) defaults to SERIAL_8N1 if not provided
1 on success, 0 on failure