Thanks for the detailed information.

I did not want to add some delay on the slave devices before responding any request, and choosed to run the converter in full duplex mode (even the Rx and Tx lines are looped).

Yes, master receives the bytes it is actually sending with this configuration. Therefore I modified the code on the master to skip the bytes it sent to the bus.

This approach seems working (even I had to modify the code on PC largely because of multithread communication issues).

Again, thanks for your usual enlightening comments.