Section 6,5: Printable_Characters

 Printable characters include the tab character (09 hex), those
 ASCII characters with codes in the range 20(hex) through 7E(hex),
 and those characters in the DEC Multinational Extension to the
 ASCII Character Set with codes in the range A1(hex) through
 FE(hex).

 Note that printable characters that are not in the Fortran
 character set (see Character_Set subtopic FORTRAN) can only appear
 in comments and character and Hollerith constants.