Anthony M7TAW has successfully got this running on 40m HF Packet. Please note as this transceiver is QRP, it is not the optimal setup, but if you pray to the sun gods it can work.
Raspberry Pi –> Digirig –> uSDX Digirig audio cable –> (tr)uSDX.
When Digirig is plugged into the raspberry pi via USB, the input and output devices required for audio will show as “USB Audio Device”. Example below for QtSoundModem.
Your PTT Port will be the ttyUSBx currently being occupied by the Digirig device. You can run ls -l /dev/serial/by-id
in a terminal to find out - the device will be named “usb-Silicon_Labs_CP2102N_USB_to_UART_Bridge_Controller” or something similar.