Due to the different firmware, some firmware, two ports can be used, some firmware can only use one of the ports. So find one of the available ports for the connection.
IF you use Qgroundcontrol for PX4 firmware ,only TELEM1 can be used ,can not use TELEM2.
IF you use Mission Planner for ardupilot firmware, find one of the available ports for the connection.
- When using Radio Telemetry connection, it must use 3DR Power Module or 5V ESC to supply power to the flight control. USB cannot be inserted because USB priority is higher than Radio Telemetry . If USB cable is plugged in, it cannot be used for radio telemetry transmission.
- The default baud rate of the Radio Telemetry is 57600, not 115200. Select the correct COM port and do not select AUTO.