IEC 61938:2013 gives guidance on current practice for the characteristics of multimedia analogue interfaces to achieve interoperability between equipment from different manufacturers. It is not a performance standard. This second edition cancels and replaces the first edition published in 1996 and constitutes a technical revision. It includes the following significant technical changes: - the values in each table were chosen with respect to the state of the art and representative of best practice in industry; - plug-in power systems and soundcard power systems are added; - a new subclause 12.3 has been created: Interoperability of portable audio headphones/earphones and portable audio equipment; - a new Annex A describing pairing and screening of conductors is added; - a new Annex B describing phantom power variants for specialized applications is also added.