Like I said before I have worked with a few blue tooth adapters and they always used a single port. No idea why your device would set up 2 ports as this is totally unnessacary any comport should have the ability to send and receive data as this is what they are designed to do.

You may be able to tell which is which based on which signals are present but without know more about the USB device in question I would not know what to tell you to look for.