Below you can find examples of conversions from xstring to string and from string to xstring.
xstring is a hexadecimal type.
data : lv_data type string,
lv_datax type xstring.
lv_data = 'Hello world!'.
lv_datax = cl_bcs_convert=>string_to_xstring( lv_data ).
data(lv_reconvert) = cl_bcs_convert=>xstring_to_string( iv_xstr = lv_datax iv_cp = '4110' ).
write : lv_reconvert.
Output : Hello world!