View source for VESA Display Power Management Signaling

'''VESA Display Power Management Signaling''' ('''VESA DPMS''') is a [[standardization|standard]] from the [[VESA]] consortium for power management of video [[Computer display|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>{{Cite web |url=http://eetd.lbl.gov/EA/Reports/39466/39466-8 |title=PC User Guide: Chapter 8<!-- Bot generated title --> |access-date=2007-04-16 |archive-url=https://web.archive.org/web/20111122155220/http://eetd.lbl.gov/EA/Reports/39466/39466-8 |archive-date=2011-11-22 |url-status=dead |df= }}</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 Extension]]s.

== Design ==

The standard defines how to signal the [[Analog television#Horizontal synchronization|H-sync]] and [[Analog television#Vertical_synchronization|V-sync]] pins in a standard [[Super Video Graphics Array|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:
{| class="wikitable"
! State !! H-sync !! V-sync !! Power !! Recovery time<ref>On a Targa TM 3820 PNLD monitor.</ref>
|- align="center"
! On
| {{yes|On}} || {{yes|On}} || 100% || n/a
|- align="center"
! Stand-by
| {{no|Off}} || {{yes|On}} || < 80% || ~1 [[second|s]]
|- align="center"
! Suspend
| {{yes|On}} || {{no|Off}} || < 30&nbsp;W || ~5 s
|- align="center"
! Off
| {{no|Off}} || {{no|Off}} || < 8&nbsp;W || ~20 s
|}

== Reception ==

By the late 1990s, most new monitors implemented at least one DPMS level.{{Citation needed|date=January 2022}}

DPMS does not define implementation details of its various power levels;<ref>{{cite web |last1=Myers |first1=Bob |title=Implications of power saving modes |url=http://repairfaq.org/sam/monfaq.htm#monimppsm |website=repairfaq.org |publisher=Samuel M. Goldwasser |access-date=9 January 2022 |language=en |quote=Energy Star and similar power-saving certifications generally don't specify what is done inside the monitor to achieve the power reduction, just the maximum power dissipation in the "reduced power" state(s).}}</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>{{cite web |title=DPMSSetTimeouts(3) |url=https://man.archlinux.org/man/DPMSSetTimeouts.3 |access-date=9 January 2022 |language=en}}</ref> and the [[XFCE]] Power Manager.<ref>{{cite web |title=XFCE Power Manager - Preferences |url=https://docs.xfce.org/xfce/xfce4-power-manager/preferences#display |access-date=9 January 2022 |language=en}}</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>{{cite web |title=Eizo FX D7, T68, TX D7, F67 User Manual |url=https://manualsdump.com/en/manuals/eizo-f67-tx_d7-fx_d7-t68/140547/31 |website=manualsdump.com |access-date=9 January 2022 |page=31 |language=en}} - implementation example.</ref>

== See also ==
* [[Display Data Channel]] DDC

== References ==

{{reflist}}

== External links ==
* [http://www.vesa.org/Standards/summary/2003_3b.htm VESA Display Power Management Signaling (DPMS) Standard] (requires purchase of the specification)
* [https://web.archive.org/web/20120627050710/http://www.vesa.org/vesa-standards/standards-summaries/ VESA Standards Listing]

[[Category:VESA|Display Power Management Signaling]]


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