Christian Drake, I attached an image that will show you the power brick and the corresponding pinout. This should answer your question. there are some great sites out there to modify your DND-323 and do not forget it's twin, Conceptronic CH3SNAS. Anyhow, check the links and you get to learn a lot about it...:-)
Good Luck and I hope this helps.
The originally attached picture
It has the diagram of the plug on the Jentec JTA0512 AC adapter label.