OK here is how it works, first of all you can change the port number you want to use with your USB-RS232 conversor, for this go to Control Panel->System-> Hardware->Device Manager. In the ports section you might find your serial port with the port it is using between () . i.e. Serial Port(COM4).

By double clicking and going to Port Configuration (i have it on spanish so i dont know the exact words) -> Advanced. There you will find a combo-box to select the number of port you want to be used by the device. Choose one tha is not Used.

On the other hand. MCSP always shows the ports to be used in a combo box (i have MCS 3.0) if the port is in use when MCS is opened it will not be shown in the combo box. Try closing all previous used programs and then open MCS, most surely.. if the port is not an option it doesn´t exist or it is in use, not being possible to be used by MCS.

I have worked with my Vaio C140G/B with this conversors with no problems before, and you should have no problem since this devices are based on the same chip.

I hope you find my post useful.

DJC