Digirig and Xiegu G90, iFTX and iPhone?

Thinking I should be able to use the digirig with my G90 and the iFTX app on my iphone/ipad. From what I understand it uses VOX and not cat control. But how do I hook it up and what are the settings on my iPhone and G90?

And

For use with iPhone you’ll need Digirig Lite which implements VOX PTT. iOS doesn’t allow apps access to serial ports so they can’t activate PTT by RTS or PTT by CAT supported by Digirig Mobile. More on that here:

https://digirig.net/choosing-digirig-model/