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.
I found something interesting.
when I convert a number using System.Convert.ToChar(X) and sends it through serial the X can only be hex:0 to hex:3F if I want to get the correct value from the other side. Any value greater than hex:3F will not be hex:3F.
for example if I send
hex:64 you will get hex:3F
send hex:E8 you will get hex:3F
It seems like it max out with a 6 bit register value,
Please help me correct this mess …