Recently, I am very interest in understanding more about these different formats:

ebcdic
ascii
hex
dec
oct
chr
Binary
Unicode

-Are there more?
-The ones that I have listed, what use do they have and when would you use it? I know some of them already.
-Why would you convert from one format to another?

I found this but really want to understand the correlations:
http://www.lookuptables.com/ebcdic_scancodes.php

I learned EBCDIC about 10 years ago but can't remember the purpose it serves for today.

Thank You