Kaye and Geoff's web page documentation 

Translation table for special characters

 Special character   Code         Special character   Code  
~%7E   !%21
#%23   $%24
%%25   ^%5E
&%26   (%28
)%29   +%2B
=%3D   {%7B
}%7D   |%7C
[%5B   ]%5D
\%5C   :%3A
"%22   ;%3B
'%27   <%3C
>%3E   ?%3F
,%2C   /%2F
space+   CR%0D
LF%0A   tab%09

This table only shows the more common special characters which are likely to be generated from a form. The control characters (ASCII values before hex 20) are also encoded as are the ASCII values greater than hex 7F (decimal 127).