UTF-16 is not quite the same thing as UCS-2.

• UCS-2 uses a single 16-bit word per character. It is therefore unable to serialize characters other than U+0000 .. U+FFFF.
• UTF-16 uses a variable number of 16-bit words per character, and is thus able to access all UNICODE characters.

Basically, UCS-2 is to UTF-16 as iso-latin-1 is to UTF-8.

There's not enough info to know whether the encoding used in the OP is UCS-2 or UTF-16. To play it safe, accept UTF-16 and send UCS-2.

Update: Noteable flaw in the comparison:

• Characters supported by UCS-2 are encoded identically in UTF-16.
• Characters may be encoded differently in iso-latin-1 and UTF-8.