What this RS-485 transceiver does on the bus
The 130 mV of receiver hysteresis helps reject noise on long or electrically noisy bus runs — a practical benefit when the cable leaves the cabinet and runs past a VFD or motor drive.
The through-hole PDIP package is a legacy-friendly footprint — easy to hand-replace on a repair bench or socket in a prototype, though it takes up more board area than a modern SOIC.
That means no last-time-buy scramble and no forced redesign for a drop-in replacement.