Millisecond Forums

I try to set a data pin of the parallel port for just 1 millisecond to high. Therefore i write the following skript and it runs, but i dont think, that the datapin is realy for just 1 millisecond on high... I contol the LEDs of a monitor to present a picture for just 1 millisecond. So the picture is loadedbefore and i turn the light on for 1 millisecond. But i can still identify the picture and in theory that should not be possible because it should be too short (subliminal perception). 

<defaults>
/screencolor = (0,0,0)
</defaults>

<picture Bilder>
/ items = ("Fruit_blackbackground.jpg", "Burger_bb.jpg", "Eg_bb.jpg")
/ position = (50, 50)
</picture>

<trial licht>
/ stimulustimes = [1000 = mysignal; 2000 = Bilder; 3008 = mysignal2; 3009 = mysignal]
/ trialduration = 4000
</trial>

<port mysignal>
/ port = lpt1
/ subport = data
/ items = ("00000000")
</port>

<port mysignal2>
/ port = lpt1
/ subport = data
/ items = ("00000100")
</port>

<block Esgibtnurein>
/ trials = [1-6 = noreplace(licht)]
/ stop = [block.Esgibtnurein.trialcount >= 6]
</block>