The MAX13442 does not typically require a pull-up resistor because RO is a push-pull CMOS output. The datasheet Electrical Characteristics table clearly guarantees the push-pull output drive capability of the receiver output. The TOCs also show curves for RO low and high drive capability.
In the cases where RO is high impedance, then a pull-up resistor would be required to pull the logic to a high state.
If the RO logic line should always idle high, then a pull-up resistor is needed when the receiver enable RE\ input is logic high (RO is high impedance). Also, consider what happens to RO when the device is shutdown (RE\ = high, and DE = low), then the RO is high impedance.