Int 14 Fn 0F  - Fossil - Enable/disable Flow Control                       [S]

   AH = 0Fh
   AL = bit mask describing requested flow control (see below)
   DX = port number

See Also: AH=09h"MBBIOS",AH=10h"FOSSIL"

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