Help with making a power supply from a laptop charger: what do these wires mean?!?

[brand0nized]

I'm trying to make the Medusa power supply that uses a 12v laptop charger. I don't have a Jack that would connect to the charger, so I want to replace the plug with a common 2.1mm dc plug, except those have 2 connections and the plug on the laptop charger has 3 wires going to it.

Here is a picture of where the cable connected to the plug meets the transformer box.

Blue is labelled "1D" and White is labeled "VOUT". The Black one is unlabeled.

Which wire should I connect to my 2.1mm dc plug?

Sent from my LT22i using Tapatalk

[rullywowr]

Pics aren't showing up, however I would suggest to grab your DMM and test to see which is hot/gnd etc.

[jubal81]

Definitely need to get the multimeter out. I also like to use tape to label the wires.

[ian_guga]

Laptop chargers have 1 extra wire that sends some signal/feedback to the laptop proving that it is the ""correct"  charger ... so that you can only by new charger from them basically.
you can ignore it. the pictures are not showing but I guess that is what you are asking about. 
here is mine made of a 24v psu I think it was for my dell or IBM ...not sure.