Utf-16BE to ISO-8859-1 in PHP

i need to convert a Utf-16BE in ISO-8859-1 in PHP (开发者_StackOverflow社区i'm not an expert in encoding so i don't know if Utf-16 and Utf-16BE are the same thing). I've read somewhere to use the mb_convert_encoding function but i haven't that function because i don't have the multibyte extension installed. So do you know an alternative method to do this?

There's also the iconv module exposing the string iconv ( string $in_charset , string $out_charset , string $str ) function.
You really don't want to code the conversion yourself, use one of those two modules.