INT 61 - Banyan VINES - ASYNC TERMINAL EMULATION - "FLOW CONTROL DATA"
	AX = 0003h subfn 03h
	DS:BX -> argument block (see #03377)
Return: AX = status (see #03369)
Desc:	this function permits the caller to freeze/unfreeze the display and
	  the ring buffer
SeeAlso: AX=0003h/SF=02h,AX=0003h/SF=06h


Format of VINES argument block for Function 0003h subfunction 03h:
Offset	Size	Description	(Table 03377)
 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