At my work most people use laptops, in combination with a stand-alone Dell LCD (connected through a VGA cable).

Problem: if you unplug your laptop from the display, the display doesn't go to sleep (it is scanning for a VGA signal), wasting full power.

Question: does there exist (i.e. , commercially available) some sort of adapter that you can plug in between the cable and the display, that would make the LCD think that a computer is connected all the time? (Similar to what a docking station would do, I assume)


I just discovered (to my surprise) that some VGA cables at our office allow the same display(s) to go into standby, while other cables do not. After some google-ing (this was useful) and tinkering, it appears that the monitor goes into standby when pin 5 is short-circuited to the ground. Although pin 5 is labeled as GND in the pin-out, apparently it is not always wired as such.

You can easily check this by short-circuiting pin 4 and pin 5 (using some kind of metal pin, e.g. easy to do using a test probe from a multimeter). If you do so, the monitor will go into standby.

So, to answer my initial question, I think we should select/buy cables where pin 5 is really wired to the ground. This shifts the problem to "how to find out before buying"

  • bring a multimeter and test? ;p – Journeyman Geek Dec 9 '11 at 9:26
  • @Journeyman: Hmm, not really practical if you buy through a webshop, or if the cable is wrapped in plastic :-) – Rabarberski Dec 9 '11 at 11:02

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