By default, SerialPort uses ASCIIEncoding to encode the characters. ASCIIEncoding encodes all characters greater then 127 as (char)63 or '?'. To support additional characters in that range, set Encoding to UTF8Encoding, UTF32Encoding, or UnicodeEncoding.
(hide) If you don't want other users to know what you are doing you can change into cloak mode in Settings (paying members only). (pauloaguia) (show all tips)