Help in these codewords

Hey wats all these codes mean in counselling.
I was just going thru opening and closing rank in aieee.
Some codes like SC ST are understandable but wat about OP, OPPH, OB, OBPH.

Wat about this AI HS?

For more information pls see

http://aieee.nic.in/ccb2009/ORCR09/Engineering/Eng/orcr.htm

and do tell me wat all these mean?????