Constant	Meaning
COMPORTHANDSHAKE_NONE	No handshaking
COMPORTHANDSHAKE_XONXOFF	XON/XOFF flowcontrol.
COMPORTHANDSHAKE_RTSCTS	RTS/CTS flowcontrol.
COMPORTHANDSHAKE_RTSCTS_TOGGLE	RTS/CTS toggle flowcontrol.
COMPORTHANDSHAKE_DTRDSR	DTR/DSR flowcontrol.