How to check coding

HiI have a table in SQL_ASCII. Clients with different language versions of 
Windows can write data in tha table using different coding systems (polish, 
english, cyrillic). Next i would like to convert each line of given column 
to UTF8, but each row can use a different coding windows-125*.

Who know how can I check coding in this rows with diffrect coding?

I tried use iconv and sql command convert, but these commands dont returns 
any errors and they can convert rows (ex. in windows-1251) from windows-1252 
to utf8 whithout any errors, but it is incorrect.

For example (in this row data is in windows-1251):

SELECT CONVERT((select "2" from langset where id_langset=1),'windows-
1250','UTF8')
I got: ĺäńôôô

SELECT CONVERT((select "2" from langset where id_langset=1),'windows-
1251','UTF8')
I got: едсффф

ICONV:
iconv -c -f WINDOWS-1250 -t UTF8 afile
ôűâŕďń÷˙ěçĺęó

iconv -c -f WINDOWS-1251 -t UTF8 a
фывапсчямзе
ку