Editing Output device (section)

== Headless operation ==
{{Multiple image
|image1=X11 ssh tunnelling.png
|caption1=[[SSH]] can be used to run programs [[remote desktop|remotely]] on a [[headless computer]] without having an output device connected
|image2=Rackmount Console (1).jpg
|caption2=A rackmount console connected to a [[KVM switch]] allows multiple computers to be used through a switchable display and [[input devices]]
|total_width=400
}}
{{Main|Headless computer}}
{{See also|Headless software}}
A computer can still function without an output device, as is commonly done with [[server (computing)|servers]], where the primary interaction is typically over a data network. A number of protocols exist over serial ports or LAN cables to determine operational status, and to gain control over low-level configuration from a remote location without having a local display device. If the server is configured with a video output, it is often possible to connect a temporary display device for maintenance or administration purposes while the server continues to operate normally; sometimes several servers are multiplexed to a single display device though a [[KVM switch]] or equivalent.

Some methods to use remote systems are:
; Remote access : The computer's [[system console|console]] can be accessed through a network connection such as the Internet, using protocols such as [[telnet]] or [[SSH]].
; [[Remote desktop]] : Allows a [[graphical user interface]] to be accessed through remote access even without a monitor.
; [[KVM switch]] : Multiple computers are connected to a single display device which can be switched between computers.
; [[Serial port]] : A serial console can be connected to access the device's console.