+-----------------------------------------------------------------+
|                                                                 |
|                           Decoded Text                          |
|                                                                 |
|                                                                 |
|  +--------------------+    downgrade    +--------------------+  |
|  | Internally encoded | --------------> | Internally encoded |  |
|  | as UTF-8           |                 | as iso-8859-1      |  |
|  | (is_utf8 = 1)      | <-------------- | (is_utf8 = 0)      |  |
|  +--------------------+     upgrade     +--------------------+  |
|                                                                 |
+-----------------------------------------------------------------+
                             |       ^    
                             |       |
                      encode |       | decode
                             |       |
                             v       |
+-----------------------------------------------------------------+
|                                                                 |
|                             Bytes or                            |
|                           Encoded Text                          |
|                                                                 |
|                                                                 |
|  +--------------------+    downgrade    +--------------------+  |
|  | Internally encoded | --------------> | Internally encoded |  |
|  | as UTF-8           |                 | as iso-8859-1      |  |
|  | (is_utf8 = 1)      | <-------------- | (is_utf8 = 0)      |  |
|  +--------------------+     upgrade     +--------------------+  |
|                                                                 |
+-----------------------------------------------------------------+

##</code><code>##

use Encode qw(is_utf8 encode decode);
binmode STDOUT,':encoding(iso-8859-1)';
my $str = "This's a \x{201c}test\x{201d}";  # This is a "decoded" str.
print "$str\n";                             # Encoded by :encoding

##</code><code>##

use Encode qw(is_utf8 encode decode);
my $str = "This's a \x{201c}test\x{201d}";  # This is a "decoded" str.
print encode('iso-8859-1', "$str\n");