Pasting in any character (except ¶ and §) in the ASCII range of 1 through 31 into a computer results in ?s to be displayed.

¶ works properly. § doesn't paste at all.

EDIT: clarified the description

When you say characters 0 to 31, which characters are you referring to? 0-31 are the ASCII control characters, none of which are typically printed besides how /t, /r and /n create whitespace.

Characters 0 through 31 are the first row of this picture: http://puu.sh/lS4Fc.png

Having typed the characters somewhere by doing alt+(num), then copying and pasting into a terminal resulted in a ?

(Character 0 can't actually be gotten using this method.)

The ComputerCraft font is basically ISO-8859-1, with extra graphical characters on the unused control characters. If you want to type characters, you'd have to input those control characters, which your keyboard probably doesn't let you do. Typing the unicode characters which happen to look like the glyphs i've drawn for said characters won't work, because those unicode characters (except the 2 you mentioned, are out of the ISO-8859-1 range)

(Basically, you have to print them from code, using string.char())

(fun fact: alt+num on windows actually looks up characters using their Dos-437 positions, not their unicode ones)