Format of DR Multiuser DOS AUX device parameter block:
Offset	Size	Description	)
 00h	BYTE	function (00h get, 01h set)
 01h	BYTE	baud rate (see #04055) FFh = don't change/unknown
 02h	BYTE	parity (see #04054)
 03h	BYTE	stop bits (00h one, 01h 1.5, 02h two, FFh unknown/don't change)
 04h	BYTE	data bits (05h-08h or FFh unknown/don't change)
 05h	BYTE	handshake (00h none, 01h DTS/DSR, 02h RTS/CTS, 04h XON/XOFF,
		FFh unknown/don't change)
 06h	BYTE	XON character, FFh unknown/don't change
 07h	BYTE	XOFF character, FFh unknown/don't change