When you add a serial port to a virtual machine, you can use a physical serial port on the host, an output file, or a named pipe.


Start the Add Hardware wizard.


Select Serial Port, and click Next.


Select the type of media you want the virtual port to access: use a physical serial port on the host, output to a file, or connect to a named pipe.


Click Next.


If you selected Use physical serial port on the host, use the drop-down menu to select the port on the host computer that you want to use for this serial connection.


If you selected Output to file, browse to the file on the host that you want to use to store the output of the virtual serial port.


If you selected Connect to named pipe, enter a pipe name in the Pipe Name field and use the drop-down menus to select the near and far ends of the pipe.

The options for the near end are client or server. The options for the far end are a process or a virtual machine.

By default, the serial port is connected when you power on the virtual machine.


(Optional) Deselect the Connect at power on check box if you do not want the serial port to connect when the virtual machine is powered on.


(Optional) Deselect the I/O mode Yield CPU on poll check box if you want to configure this serial port to use interrupt mode as opposed to polled mode.

Polled mode is of interest primarily to developers who are using debugging tools that communicate over a serial connection. Polled mode causes the virtual machine to consume a disproportionate share of CPU time. This makes the host and other guests run sluggishly.


(Optional) To maintain best performance for applications on the host, select the Yield CPU on poll check box.

This forces the affected virtual machine to use interrupt mode, which yields CPU time if the only task it is trying to do is poll the virtual serial port.


Review the information on the Ready to Complete page, and click Finish.