The RS485 interface (Recommended Standard 485) is used for data communication over long distances. Data is transmitted bidirectionally via a pair of wires at a data rate of up to 12 Mbps. The symmetrical line increases the electromagnetic interference immunity. Since the protocol is not standardized, implementations of different manufacturers are rarely compatible with each other.
RS422 differs essentially in the use of 2 pairs of wires, each of which is used unidirectionally. Mostly 9-pole D-Sub variants are used as connectors.
Würth Elektronik Webinar: Signal interface filters - effectiveness under real conditions