SerialPort.Write Method (String)
Writes the specified string to the serial port.
Assembly: System (in System.dll)
Use this method when you want to write a string as output to a serial port.
By default, SerialPort uses ASCIIEncoding to encode the characters. ASCIIEncoding encodes all characters greater than 127 as (char)63 or '?'. To support additional characters in that range, set Encoding to UTF8Encoding, UTF32Encoding, or UnicodeEncoding.