Whew, I'm glad of that, as I would be of no help with IOS. Now to Device Manager:
1. Open the Windows Start menu, and in the search box enter "device manager". This should show it at the top of a list of other, non-relevant items.
2. Click on it and it should start, showing you a long list of a host of items installed in or connected to your PC, most of which you are unlikely to be aware of. Find the item "Ports (COM & LPT)".
3. Click on the ">" icon to the left of this and your converter should show up as "ATEN USB to Serial Bridge (COMn)", or whatever your converter happens to be. The 'COMn' gives you the COM-port number that you needed to tell your Gemini controlling application it should use. (You could double-click on this item to see its properties, including the 'Port Settings' pane that shows the settings the converter uses to communicate between your PC USB port and Gemini; mine is currently at 15200/8/None/1/None.)
If your item shows as something other than an ATEN, then this might be the root of your communication problems, as ASiair runs on an Android-like o/s, and there is likely to be far fewer drivers available for your these types of devices.
Please let me know how you go. Currently in the UK, hey! You must be up late to conduct this discussion!
Paul.