IEC_61938-2018.pdf

IEC 61938 Edition 3.0 2018-01 INTERNATIONAL STANDARD Multimedia systems Guide to the recommended characteristics of analogue interfaces to achieve interoperability IEC 61938:2018-01(en)THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2018 IEC,Geneva,Switzerland All rights reserved.Unless otherwise specified,no part of this publication may be reproduced or utilized in any form or by any means,electronic or mechanical,including photocopying and microfilm,without permission in writing from either IEC or IECs member National Committee in the country of the requester.If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,please contact the address below or your local IEC member National Committee for further information.IEC Central Office Tel.:+41 22 919 02 11 3,rue de Varemb Fax:+41 22 919 03 00 CH-1211 Geneva 20 infoiec.ch Switzerland www.iec.ch About the IEC The International Electrotechnical Commission(IEC)is the leading global organization that prepares and publishes International Standards for all electrical,electronic and related technologies.About IEC publications The technical content of IEC publications is kept under constant review by the IEC.Please make sure that you have the latest edition,a corrigenda or an amendment might have been published.IEC Catalogue-webstore.iec.ch/catalogue The stand-alone application for consulting the entire bibliographical information on IEC International Standards,Technical Specifications,Technical Reports and other documents.Available for PC,Mac OS,Android Tablets and iPad.IEC publications search-www.iec.ch/searchpub The advanced search enables to find IEC publications by a variety of criteria(reference number,text,technical committee,).It also gives information on projects,replaced and withdrawn publications.IEC Just Published-webstore.iec.ch/justpublished Stay up to date on all new IEC publications.Just Published details all new publications released.Available online and also once a month by email.Electropedia-www.electropedia.org The worlds leading online dictionary of electronic and electrical terms containing 20 000 terms and definitions in English and French,with equivalent terms in 16 additional languages.Also known as the International Electrotechnical Vocabulary(IEV)online.IEC Glossary-std.iec.ch/glossary 65 000 electrotechnical terminology entries in English and French extracted from the Terms and Definitions clause of IEC publications issued since 2002.Some entries have been collected from earlier publications of IEC TC 37,77,86 and CISPR.IEC Customer Service Centre-webstore.iec.ch/csc If you wish to give us your feedback on this publication or need further assistance,please contact the Customer Service Centre:csciec.ch.IEC 61938 Edition 3.0 2018-01 INTERNATIONAL STANDARD Multimedia systems Guide to the recommended characteristics of analogue interfaces to achieve interoperability INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 33.160.01,35.200 ISBN 978-2-8322-5056-3 Registered trademark of the International Electrotechnical Commission Warning!Make sure that you obtained this publication from an authorized distributor.2 IEC 61938:2018 IEC 2018 CONTENTS FOREWORD.5 INTRODUCTION.7 1 Scope.8 2 Normative references.10 3 Terms and definitions.10 4 General conditions.13 5 Power supply.13 5.1 Alternating current(AC)power supply voltages and frequencies.13 5.2 Direct current(DC)power supply voltages.14 5.3 Power supply feed for microphones.14 6 Interconnections.14 6.1 Connections.14 6.1.1 General.14 6.1.2 Characteristics of cables.14 6.2 Connectors.16 7 Marking and symbols for marking.16 7.1 Marking.16 7.2 Symbols for marking.16 8 Electrical recommended values.16 8.1 General purpose output/input.16 8.2 General purpose audio output/input.16 8.2.1 Audio-only interfaces for consumer equipment.16 8.2.2 Interfaces for professional equipment and consumer equipment where audio and video signals are present on the same connector or cable.17 8.3 General purpose video input/output.19 9 Interoperability of microphones and amplifiers.19 9.1 Microphones(excluding piezoelectric types).19 9.2 Power supply feed for electret microphones fed over a signal conductor(“plug-in power”).20 9.3 Power supply feed for electret microphones fed by a separate conductor(soundcard power or PC power).21 9.4 Phantom supply system.21 9.4.1 General.21 9.4.2 Supply voltage polarity.21 9.4.3 Circuit diagram.22 9.4.4 Value of the supply voltage.22 9.4.5 Supply current.22 9.4.6 Marking.22 9.5 A-B supply system.23 9.5.1 General.23 9.5.2 Output impedance of the microphone.23 9.5.3 Circuit diagram.23 9.5.4 Connection of the power supply to earth.23 9.5.5 Marking.23 9.6 Polarity of the audio frequency voltage.23 10 Interoperability of record-playing units(pick-ups)and amplifiers.25 IEC 61938:2018 IEC 2018 3 11 Interoperability of loudspeakers and amplifiers.26 11.1 Single unit loudspeakers.26 11.2 Loudspeaker systems.26 11.2.1 Loudspeakers with b