Binary    Hex  Char  ASCII: Hex Binary
00 0000 = 00 = '@'          40  100 0000
00 0001 = 01 = 'A'          41  100 0001
  :
00 1111 = 0F = 'O'          4F  100 1111
01 0000 = 10 = 'P'          50  101 0000
  :
01 1111 = 1F = '_'          5F  101 1111
10 0000 = 20 = ' '          20  010 0000
  : 
10 1111 = 2F = '/'          2F  010 1111
11 0000 = 30 = '0'          30  011 0000 
  :
11 1001 = 39 = '9'          39  011 1001
  :
11 1111 = 3F = '?'          3F  011 1111