IEC 61938:2018 is available as \/2 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. 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.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 2<\/td>\n | undefined <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | CONTENTS <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | 1 Scope <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | Figures Figure 1 \u2013 Audio and video sources and destinations <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 2 Normative references 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 4 General conditions 5 Power supply 5.1 Alternating current (AC) power supply voltages and frequencies <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 5.2 Direct current (DC) power supply voltages 5.3 Power supply feed for microphones 6 Interconnections 6.1 Connections 6.1.1 General 6.1.2 Characteristics of cables Tables Table 1 \u2013 Direct current (DC) power supply voltages and tolerances <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 6.2 Connectors 7 Marking and symbols for marking 7.1 Marking 7.2 Symbols for marking 8 Electrical recommended values 8.1 General purpose output\/input 8.2 General purpose audio output\/input 8.2.1 Audio-only interfaces for consumer equipment Table 2 \u2013 General purpose values for audio-only interfaces <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 8.2.2 Interfaces for professional equipment and consumer equipment where audio and video signals are present on the same connector or cable <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | Table 3 \u2013 General purpose values for audio signals for professional interfaces <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 8.3 General purpose video input\/output 9 Interoperability of microphones and amplifiers 9.1 Microphones (excluding piezoelectric types) Table 4 \u2013 General purpose recommended values for video signals <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | 9.2 Power supply feed for electret microphones fed over a signal conductor (\u201cplug-in power\u201d) Table 5 \u2013 Recommended values for microphones and amplifiers <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | 9.3 Power supply feed for electret microphones fed by a separate conductor (“soundcard power” or “PC power”) 9.4 Phantom supply system 9.4.1 General 9.4.2 Supply voltage polarity <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | 9.4.3 Circuit diagram 9.4.4 Value of the supply voltage 9.4.5 Supply current 9.4.6 Marking <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | 9.5 A-B supply system 9.5.1 General 9.5.2 Output impedance of the microphone 9.5.3 Circuit diagram 9.5.4 Connection of the power supply to earth 9.5.5 Marking 9.6 Polarity of the audio frequency voltage Figure 2 \u2013 Example of plug-in power system for a single microphone <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | Figure 3 \u2013 Example of plug-in power system for a two-channel microphone Figure 4 \u2013 Example of soundcard power system Figure 5 \u2013 Example of phantom power supply system <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | 10 Interoperability of record-playing units (pick-ups) and amplifiers Figure 6 \u2013 Example of A-B power supply system Table 6 \u2013 Required values for phantom supply systems Table 7 \u2013 Required values for A-B power supply systems Table 8 \u2013 Recommended values for analogue record-playing units and amplifiers <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | 11 Interoperability of loudspeakers and amplifiers 11.1 Single unit loudspeakers 11.2 Loudspeaker systems 11.2.1 Loudspeakers with built-in amplifier 11.2.2 Impedance-defined loudspeaker systems Table 9 \u2013 Recommended values for impedance-defined loudspeaker systems <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | 11.2.3 Constant voltage loudspeaker systems 11.3 Voltage (or power) interoperability of amplifiers and loudspeakers 11.3.1 Overview 11.3.2 Interoperability requirements Table 10 \u2013 Recommended values for constant voltage loudspeaker systems <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | 11.4 Polarity of the sound pressure 12 Interoperability of headphones and amplifiers 12.1 General 12.2 Interoperability of headphones with stationary amplifiers Table 11 \u2013 Recommended values for headphonesand amplifiers in stationary applications <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | 12.3 Interoperability of portable audio headphones\/earphones and portable audio equipment 12.3.1 General 12.3.2 Portable audio headphones\/earphones 12.3.3 Portable audio equipment 12.3.4 Recommended values and input\/output values for portable audio headphones\/earphones and portable audio equipment Table 12 \u2013 Recommended values for portable audio headphones\/earphones and portable audio equipment <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | 13 Interoperability of amplifiers with other amplifiers 13.1 Pre-amplifiers and power amplifiers for general purpose and sound reinforcement <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | 13.2 Broadcast and similar line amplifiers Table 13 \u2013 Recommended values for pre-amplifiers and power amplifiers Table 14 \u2013 Recommended values for broadcast and similar line amplifiers <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | Annex A (informative) Pairing and screening of conductors <\/td>\n<\/tr>\n | ||||||
| 38<\/td>\n | Annex B (informative) Phantom power variants for specialized applications Figure B.1 \u2013 Caution symbol <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Multimedia systems. Guide to the recommended characteristics of analogue interfaces to achieve interoperability (GMT)<\/b><\/p>\n |