I tried, but any COM I choose end-up with the same error message:
"The port that the modem is using is currently open by another application"
Looks like the message refers to an APPLICATION, not to a port. If I'm right, then I should detect an application. I tried, but got nowhere.
If it's a COM port problem, then there's another piece of information to which I don't have an explanation, the Ports section in the device manager reports of the availability of COM1 and LPT1. Shouldn't I see also a COM2?