SAP has different numbers that are used to indicate which character encoding will be used for different things, SAP calls it "code page number", for example, for UTF-8 it would be 4110 while for UTF-16 it would be 4102.
Don't take my word for this, SAP has a table where you can check this by yourself. Table "TCP00" stores different codes and the name of its correspondent encoding, and if you check that table you will notice that for example 4103, 4104 and 4105 are also Unicode encoding codes (With some variations).
A more real example:
If we want to export an Excel (Not available anymore, check notes 2083705, 2094034, 1776721, 975868) CSV file by using "GUI_DOWNLOAD" encoded as a "UTF-16" file, then at the exporting parameter "CODEPAGE", pass value "4102" and you will get a fresh new UTF-16 CSV file.