What's the difference between ASD (automatic slip differential) and LSD (limited-slip differential) ?

My understanding is that ASD has hydraullic-lines to the diff, while LSD is self-contained within the diff.

I believe they are also NOT interchangeable. That is, if your car has a LSD, you can't install an ASD instead, and vice-versa.

Can someone please confirm?

Thanks,
:-) neil
1988 360TE AMG (with 3.07 LSD, looking for a 2.87 LSD)
1993 500E (looking for a 3.07 ASR)