No, the only way to guarantee a LOW output on RO is to have the differential receiver input voltage (Va-Vb) less than or equal to Vth_L which is -50mV. Because the differential voltage between A and B is pulled to 0V by the 120 Ohm termination resistor during an open or short event, the RO output is forced to a HIGH voltage as its fail-safe. Most RS422 parts have the same result because the EIA/TIA-485 standard specifies a -50mV to -200mV differential voltage to cause an output LOW on RO.