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.

You can configure a virtual serial port in several ways.

Use physical serial port on the host

Uses an external modem or a hand-held device in your virtual machine.

Output to file

Captures the data that a program running in the virtual machine sends to the virtual serial port.

Connect to a named pipe

Enables two virtual machines or a virtual machine and a process on the host to communicate as if they were physical machines connected by a serial cable. For example, this can be used for remote debugging on a virtual machine.

Connect via a remote network

Enables a serial connection to and from a virtual machine's serial port over the network.

Virtual Serial Port Concentrator (vSPC) aggregates traffic from multiple serial ports onto one management console. It behaves similarly as physical serial port concentrators. Using a vSPC also allows network connections to a virtual machine's serial ports to migrate seamlessly when the virtual machine is migrated using vMotion.

Verify that the virtual machine is powered off.

Required privilege: Virtual Machine .Configuration.Add or Remove Device


In the vSphere Client inventory, right-click the virtual machine and select Edit Settings.


Click the Hardware tab and select Add.


Select Serial Port, and click Next.


On the Serial Port Type page, select the type of media for the port to access.



Use physical serial port on the host

Click Next and select the port on the host computer that you want to use for this serial connection from the drop-down menu.

Output to file

Click Next and browse to the location of the file on the host to store the output of the virtual serial port.

Connect to named pipe


Click Next and in the Pipe Name and Attributes panel, use the default pipe name or enter another pipe name.


Select the Near end and Far end of the pipe from the drop-down menus.

Connect over the Network


Click Next and select Server or Client.


Enter a Port URI or select Use Virtual Serial Port Concentrator (vSPC) and enter the vSPC URI location.

Select the vSPC option if vSPC is used as an intermediate step to access all virtual machines through a single IP address. The URI is the remote end of the serial port to which the virtual machine's serial port should connect.


(Optional) Change the Device status settings.




Connects or disconnects the device while the virtual machine is running.

Connect at power on

Connects the device whenever you power on the virtual machine. You can change this setting when the virtual machine is either powered on or powered off.


Select an I/O Mode.

To maintain best performance for applications on the host, select Yield CPU on poll and click Next.

This option 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.

Deselect Yield CPU on Poll to configure this serial port to use interrupt mode as opposed to polled mode and click Next.

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.


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