How to set the TDD status from Tx to Rx or to other status in IIO?

Hello,

I want to test the TDD mode in IIO Oscilloscope. And I open the FMComms2 Advanced window, there is a selection TDD. If I check the TDD, how to set the status Rx and Tx? What is the meaning of the Use Dual Synth, Use FDD VCO tables?

Thanks and best regards,

Wei