Define com-port to use for serial connection ?

This article will help answer this commonly asked question

In LinkManager you can predefine the COM port used for serial communication.

Right-click the tray icon (might be hidden, click the ^ symbol in the Windows system tray).
Select "Options"
And type in the com port number you wish to assign to the serial port emulator (com0com)

NOTE: Changing the COM port while connected to an agent is not recommended Some other factors can have an effect on a successful change or set of the COM port but not covered here.

If you experience issues changing the COM port you can try a reboot of the PC – the only guaranteed solution to release a COM port in Windows. You can always monitor the actual COM port setting by searching for the “com0com” device in the Windows Device Manager.