COM2 is generally used for CAT in RemoteRig installations. This can be used
at the control end either by standard serial cable, or by turning USB support
on and using a USB cable instead. The radio side only uses a serial cable, the
control side is flexible. One of my checklists that I send on request walks users
through the process of setting CAT up over the RRC's.
An exception is the "Twin" products, which use the CAT port to communicate
with each other. Therefore, one must use COM1 in mode-6 or 7 for CAT
instead, but you can choose to use either USB or serial on the control side. In
the case of the "Twin" products, the "Winkeyer" function can therefore not be
used if you are using CAT on the control side, you are correct. A solution would
be a virtual port as you suggest.
Otherwise, I installed serial servers in several installations to control serial devices,
since you only have one port plus CAT, or no ports on "Twin" products, available on
the RRC's. I therefore tend not to use RRC's to control amplifiers, rotors, wattmeters,
etc. The Webswitch can also be used to control some devices, I even use them to raise
and lower masts.
73,
Mitch DJ0QN / K7DX