TBS Crossfire Telemetry
The TBS Crossfire RX can be connected to the Pixhawk through the I2C bus and it will act as a MavLink telemetry transceiver. The Crossfire TX uses Bluetooth for connecting to the GCS (QGroundControl supports it).
You need a cable to interface the 5-Pin TBS connector to the 4-Pin I2C connector used by the Pixhawk (or its I2C Hub)
Only 3 out of the 5 pins are needed:
Only 3 out of the 4 pins are needed. Showing a connection using the I2C Hub: