IEC 60870-6-503:2014 specifies a method of exchanging time-critical control centre data through wide-area and local-area networks using a full ISO compliant protocol stack. It contains provisions for supporting both centralized and distributed architectures. This standard includes the exchange of real-time data indications, control operations, time-series data, scheduling and accounting information, remote program control and event notification. This new edition includes the following significant technical changes with respect to the previous edition:- certain objects were made informative;- services associated with the informative objects were made informative;- certain TASE.2 conformance blocks were made out-of-scope.