Bitfields for FOSSIL requested flow control:
Bit(s)	Description	)
 0	XON/XOFF on transmit (watch for XOFF while sending)
 1	CTS/RTS (CTS on transmit/RTS on receive)
 2	reserved
 3	XON/XOFF on receive (send XOFF when buffer near full)
 4-7	all 1