Serial communication:

 
Voice commands and remote file management by the QMP can utilize the Bluetooth serial connection.  Alternatively, the IN port on the back of the Quadstick, normally used as a switch input, can be used as a physical serial connection with a FTDI, Future Technology Devices International Ltd TTL-232R-3V3-AJ cable, if the Bluetooth serial connection is not available.
 
The Quadstick Manager program will automatically search for any available serial connection to the Quadstick at startup.