VESA Display Power Management Signaling

VESA Display Power Management Signaling (VESA DPMS) is a standard from the VESA consortium for power management of video monitors. Example usage includes turning off, or putting the monitor into standby after a period of idle time to save power. Some commercial displays also incorporate this technology.

History

VESA issued DPMS 1.0 in 1993,<ref>Template:Cite web</ref> basing their work on the United States Environmental Protection Agency's (EPA) earlier Energy Star power management specifications. Subsequent revisions were included in future VESA BIOS Extensions.

Design

The standard defines how to signal the H-sync and V-sync pins in a standard SVGA monitor to trigger the monitor's power saving capabilities.

DPMS defines four modes: normal, standby, suspended and off. When in the "off" state, some power may still be drawn in order to power indicator lights.

The standard is:

State	H-sync	V-sync	Power	Recovery time<ref>On a Targa TM 3820 PNLD monitor.</ref>
On	Template:Yes	Template:Yes	100%	n/a
Stand-by	Template:No	Template:Yes	< 80%	~1 s
Suspend	Template:Yes	Template:No	< 30 W	~5 s
Off	Template:No	Template:No	< 8 W	~20 s

Reception

By the late 1990s, most new monitors implemented at least one DPMS level.Template:Citation needed

DPMS does not define implementation details of its various power levels;<ref>Template:Cite web</ref> while in a CRT-based display the three steps could logically be mapped to three blocks to be shut down in order of increasing savings, thermal stress, and warm-up time (video amplifier, deflection, filaments) not all designs would be trivially adaptable to this model, and neither would the technologies that commercially succeeded CRT monitors.

Partially due to this reason, most major operating environments (such as Microsoft Windows and the MacOS family) do not implement the 3-level DPMS specification either, offering only a single timer. Notable exceptions include X11<ref>Template:Cite web</ref> and the XFCE Power Manager.<ref>Template:Cite web</ref>

DPMS competed with the alternative Nutek power saving system, in which the monitor recognizes a black picture produced by a screensaver and enters a power saving mode after an appropriate delay.<ref>Template:Cite web - implementation example.</ref>

See also

• Display Data Channel DDC

External links

• VESA Display Power Management Signaling (DPMS) Standard (requires purchase of the specification)
• VESA Standards Listing

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