In summary, for serial, wired data transmission covering long distances, at high data rates, or in harsh environments, it is necessary to apply the RS-485 and RS-422 standards. Their differential signaling format and twisted pair cabling picks up most noise as a common mode signal which is effectively rejected by the differential receiver. Wide common mode range minimizes ground potential difference effects that arise from nodes communicating at long distances. Both standards support distances up to 4,000’ at low data rates of about 100 kbps or less, above 100 kbps the distance drops by a factor of approximately ten for each 10x increase in data rate. There are three basic transceiver types used for RS-422 and RS-485. The most commonly used is the 8-lead half duplex version in which the driver outputs and receiver inputs share pins on the package, simplifying the interface to a single, bidirectional cable. The next commonly used transceiver is the 14-lead full duplex type, in which the driver outputs and receiver inputs utilize separate pins for connection to the busses. The third transceiver type is the 8-lead full duplex version with no enable connections, useful for only single driver, RS-422 type busses. ESD ratings are very important for interface ICs, Renesas offers both HBM and IEC61000 specified RS-485 ICs.