public int getMaxPacketSize ()
    {
	int	field = getU16 (4);
	int	size = field & 0x3ff;
	String	type = getType ();
	boolean	highspeed = iface.getDevice ().getSpeed () == "high";

	// "high bandwidth" mode may use multiple packets per microframe
	if (highspeed && (type == "iso" || type == "interrupt"))
		size *= 1 + (field >> 11) & 0x03;
	return size;
    }