 RS-422 is the common short form title of American National Standards Institute (ANSI) standard "ANSI/TIA/EIA-422-B Electrical Characteristics of Balanced Voltage Differential Interface Circuits" and its international equivalent
"ITU-T Recommendation T-REC-V.11", also known as "X.27".These technical standards specify the electrical characteristics of the balanced voltage digital interface circuit.RS-422 provides for data transmission, using balanced, or differential, signaling, with unidirectional/non-reversible, terminated or non-terminated transmission lines, point to point, or multi-drop.