I have Xrandr 1.2 version, when I give Xrandr -q or xrand -query
I get following output::::

# xrandr --query
SZ: Pixels Physical Refresh
*0 1600 x 1200 ( 310mm x 231mm ) *69 68 67
1 1280 x 1024 ( 310mm x 231mm ) 80 79 78
2 1024 x 768 ( 310mm x 231mm ) 105 104 103
3 800 x 600 ( 310mm x 231mm ) 133 132 131
4 1400 x 1050 ( 310mm x 231mm ) 75 60
5 1280 x 960 ( 310mm x 231mm ) 85 60
6 1152 x 864 ( 310mm x 231mm ) 75
7 1152 x 768 ( 310mm x 231mm ) 55
8 928 x 696 ( 310mm x 231mm ) 60
9 896 x 672 ( 310mm x 231mm ) 60
10 832 x 624 ( 310mm x 231mm ) 75
11 700 x 525 ( 310mm x 231mm ) 75 60
12 640 x 512 ( 310mm x 231mm ) 75 60
13 640 x 480 ( 310mm x 231mm ) 85 75 73 60
14 720 x 400 ( 310mm x 231mm ) 85
15 640 x 400 ( 310mm x 231mm ) 85
16 576 x 432 ( 310mm x 231mm ) 75
17 640 x 350 ( 310mm x 231mm ) 85
18 576 x 384 ( 310mm x 231mm ) 55
19 512 x 384 ( 310mm x 231mm ) 85 75 70 60 87
20 416 x 312 ( 310mm x 231mm ) 75
21 400 x 300 ( 310mm x 231mm ) 85 75 72 60 56
22 320 x 240 ( 310mm x 231mm ) 85 75 73 60
23 360 x 200 ( 310mm x 231mm ) 85
24 320 x 200 ( 310mm x 231mm ) 85
25 320 x 175 ( 310mm x 231mm ) 85
Current rotation - normal
Current reflection - none
Rotations possible - normal
Reflections possible - none


Thus, I am unable to know which mode is currently connected(i.e VGA, LVSD, DVI etc.)

Basically I want to simulate turning on and off of my Monitor.

I am doing
$ xrandr –output VGA-0 –off

but, its not working.

Any help in this respect is greatly appreciated.

My xrandr version is 1.1 so I should not reply... it doesn't support any
-output flag.
On my laptop I have a ATI radeon card and when using an external monitor I'm able to select which monitor to turn off by means of the radeontool utility - maybe if you have such a card you can do the same thing.
And if you want to turn off both monitors, you can type: xset dpms force off
I know I haven't replied to your actual question, but if you didn't know about these tricks maybe this can help you