Here's a pic of the connector: http://support.dell.com/support/edocs/dta/316LT/00000008.htm
It's 16 volts/2 amps.
I think, looking at the pic link, the hole at indent is ground, and right above it is positive, although you should verify this with a ohm meter or asking someone, or emailing Dell.
I have one if you are still asking for information about it.
I'm just about to take a bunch of pics of my Dell 316lt to list it on eBay. I'll put a multi meter on the brick and post here for you or anyone else looking for that info.
Bummer I have one of these (but it is missing parts internally). I think the power connection is just 16V on 2 pins and the 3rd pin is just an index hole so you don't plug it in backwards.