use Encode qw(encode decode);

    my $iso_data=encode('iso-8859-1',decode('UTF-8',$utf8_data));

##</code><code>##

koi8-r
dingbats
iso-8859-10
iso-8859-13
cp37
iso-8859-9
iso-8859-6
iso-8859-1
cp1047
iso-8859-4
Internal
iso-8859-2
symbol
iso-8859-3
US-ascii
iso-8859-8
iso-8859-14
UCS-2
iso-8859-5
UTF-8
iso-8859-7
iso-8859-15
cp1250
iso-8859-16
posix-bc