A virtual machine can use up to four virtual serial ports. The virtual serial port can connect to a physical serial port or to a file on the host computer. It can also be used to set up a direct connection between two virtual machines or a connection between a virtual machine and an application on the host computer by using a host-side-named pipe.


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


Click the Hardware tab, and select a Serial port in the Hardware list.


(Optional) Change the Device status settings.




To connect or disconnect the device while the virtual machine is running.

Connect at power on

To connect 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 a connection type.



Use physical serial port

Select Use physical serial port for the virtual machine to use a physical serial port on the host computer.

Use output file

Select Use output file to send output from the virtual serial port to a file on the host computer. Use the drop-down menu to select a serial port to use.

Use named pipe


Select Use named pipe to set up a direct connection between two virtual machines or a connection between a virtual machine and an application on the host computer.


Use the default pipe name or enter another pipe name in the Pipe Name list.

For a serial pipe for a virtual machine on an ESX/ESXi host, type /tmp/socket or another UNIX socket name.


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

Connect over the network


Select Use network to connect through a remote network.


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.


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.


Click OK to save your changes and close the dialog box.