You are using
Encoding::ASCII[
^]. This will replace all non ASCII characters (highest bit set) by a question mark character.
You may send the characters as they are without performing any conversion. If your data use some kind of text encoding, sender and receiver must use the same encoding. Alternatively convert the text before sending to an encoding defined by you or provide the encoding separately so that the receiver can convert it if necessary.
The term 'Extended ASCII' is really misleading and should be avoided (see also in the
Wikipedia[
^]).