This part of IEC 62026 specifies a method for communication between a single control device and switching elements, and establishes a system for the interoperability of components with the specified communication interfaces. The complete system is called 'Actuator Sensor interface (AS-i)'. This second edition of IEC 62026-2 cancels and replaces the first edition published in 2000. This second edition constitutes a technical revision. The main changes with respect to the previous edition are as follows: doubling the number of slaves from 31 to 62 by introduction of sub-addresses; introduction of AS-I safety system.