Follow the instructions in the manual regarding the USB driver. When the CPAP was first plugged in, it went to windows update looking for the USB-serial driver even when I had already pre-installed the driver. It could not find the device, but this was anticipated and covered in the instructions. There is a manual and an auto detect function in the drop down menu for the software setting the com port.
Subsequently, a pop-up said it found the driver and was installed. I then used the auto detect and the com port automatically set itself. For this setup I was using an Asus laptop with USB cable to the CPAP.
You don't need to go through the above if you use the SD card. Interestingly the SD card is not a 'leave in' feature like in the Resmed but more as a medium for data transfer. The CPAP will auto copy data to the card once it's inserted and will indicate end once the process is completed and the card is ready for removal. Guess it has a built in software eject function to protect the card.
The software provides the necessary basic information. One graph covers A, H & S. Another covers pressure, and the third covers leaks. You won't get all the other graphs in Sleephead, which I haven't learnt to use or interpret.
The Apex XT auto is very quiet. Does not feel like a hurricane during the night even when the mask leaks. The Mrs slept through the night without disturbance from air gushing out from the mask port. The graphs seem to bear this out as pressures in APAP mode appear generally lower than that shown in Sleepyhead for the S9/A10. The min pressure was set at 4 to allow the algorithm and the machine to adjust from there. I guess if one needs a higher pressure floor, just set the min pressure higher.
If I hadn't been able the get my hands on the full version of the software, I wouldn't have bought the Apex XT Auto. I'm now good to go!