The first edition of IEC 61938 has been derived from IEC 60268-15, IEC 60574-4 and IEC 60933-1 and also from related proposals which had been submitted up until the date of this revision. IEC 60268-15 was the first standard to address 'interoperability' - the ability of equipment from different manufacturers to be assembled into a system with full compatibility at every 'interface'. The purpose, terminology and effects of IEC 61938, however, are often misinterpreted considering IEC 61938 to be a performance standard which had never been intended. The aim of this revision is to make the intention of this standard easily comprehensible by using widely used terminology in the title and text of the standard. The features of the revision are the following: a) unification and arrangement of existing related standards, including currently submitted proposals; b) the concept of a "General purpose output/input". The committee responsible is DKE/K 742 "Audio-, Video- und Multimediasysteme, -geräte und -komponenten" of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.