IEC 61938:2018 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. Recommendations for interfaces for equipment used in vehicles, and for analogue video interfaces for broadcast and similar equipment, are not given. Refer to IEC 60958 for the interconnection of digital signals. This third edition cancels and replaces the second edition published in 2013. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:a) electric tolerance is standardized;b) recommended value of output source impedance is adjusted;c) value of 6 Ohms is additionally recommended to impedance-defined loudspeaker systems;d) values in each table are chosen with respect to the state of the art and representative of best practice in industry.