Int 61 Fn 0003  - Banyan Vines - Async Terminal Emulation - "flow Control  [N]

   AX = 0003h subfn 03h
   DS:BX -> argument block (see #3048)

Return: AX = status (see #3040)
Desc:  this function permits the caller to freeze/unfreeze the display and
     the ring buffer

See Also: AX=0003h/SF=02h,AX=0003h/SF=06h

Format of VINES argument block for Function 0003h subfunction 03h:
Offset Size    Description (Table 3048)
 00h   BYTE    session ID (00h)
 01h   BYTE    03h (function "flow control data")
 02h   BYTE    flow control flag
       00h allow characters to be put into display or ring buffer
       01h don't place any more characters into display or ring buffer