What is the difference between RS-422 and RS-485?
RS-422 provides a balanced, full-duplex, 4-wire serial interface for point-to-point links. RS-485 offers balanced, serial 2-wire (half-duplex) or 4-wire interfacing (full-duplex) suitable for constructing a data bus. RS-485 outputs can be individually set to a high-impedance, inactive state (‘tristate’) and can therefore be wired in parallel.