A "COM port" has nothing to do with COM and ActiveX.

Excel topics really belong in the Office Development forum and not the programming forums here. Office VBA macro scripting is included there as a courtesy though it doesn't really belong here at all.

Consumer SKUs of Office (and Excel) do not incude any serial port controls or any license allowing you to "borrow" controls such as those shipped as part of VB6. For this you'd need Office Developer Edition (or the equivalent for versions of Office after XP/2002).

You might also look for some 3rd party library intended for this purpose.