1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationDigital audio Digital input-output interfacing Transmission of digital audio over asynchronous transfer mode (ATM) networksBS EN 62365:2009National forewordThis British Standard
2、is the UK implementation of EN 62365:2009. It is identical to IEC 62365:2009. It supersedes BS EN 62365:2005 which is withdrawn.The UK participation in its preparation was entrusted to Technical CommitteeEPL/100, Audio, video and multimedia systems and equipment.A list of organizations represented o
3、n this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. BSI 2010ISBN 978 0 580 63672 1ICS 33.160.30 35.200Compliance with a British Standard cannot confer im
4、munity fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 30 April 2010.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 62365:2009EUROPEAN STANDARD EN 62365 NORME EUROPENNE EUROPISCHE NORM
5、 July 2009 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: Avenue Marnix 17, B - 1000 Brussels 2009 CENELEC - All rights of exploitation in any form and by any means
6、reserved worldwide for CENELEC members. Ref. No. EN 62365:2009 E ICS 35.200; 33.160 Supersedes EN 62365:2005English version Digital audio - Digital input-output interfacing - Transmission of digital audio over asynchronous transfer mode (ATM) networks (IEC 62365:2009) Audionumrique - Interface numri
7、que dentre-sortie - Transmission de laudionumrique sur les rseaux mode de transfert asynchrone (ATM) (CEI 62365:2009) Digitalton - Digitale Ein-/Ausgangsschnittstellen - bertragung von Digitalton ber ATM-Netzwerke (IEC 62365:2009) This European Standard was approved by CENELEC on 2009-06-01. CENELEC
8、 members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on appl
9、ication to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretar
10、iat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Ne
11、therlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 62365:2009EN 62365:2009 2 Foreword The text of document 100/1517/FDIS, future edition 2 of IEC 62365, prepared by technical area 4, Digital systems interfaces and protocols, of
12、IEC TC 100, Audio, video and multimedia systems and equipment, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 62365 on 2009-06-01. This European Standard supersedes EN 62365:2005. The main changes with respect to EN 62365:2005 are listed below: second, third and fou
13、rth required formats in 4.3 removed; 4.3 reformatted, eliminating Table 2, and subsequent tables renumbered. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2010-03-01 latest
14、date by which the national standards conflicting with the EN have to be withdrawn (dow) 2012-06-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 62365:2009 was approved by CENELEC as a European Standard without any modification. In the official v
15、ersion, for Bibliography, the following note has to be added for the standard indicated: IEC 60027-2 NOTE Harmonized as EN 60027-2:2007 (not modified). _ BS EN 62365:2009 3 EN 62365:2009 Annex ZA (normative) Normative references to international publications with their corresponding European publica
16、tions The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. NOTE When an international publication has
17、been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 60958-1 - 1)Digital audio interface - Part 1: General EN 60958-1 2008 2)IEC 60958-4 - 1)Digital audio interface - Part 4: Professional applications (TA4) EN 60958-4 2003 2)ITU
18、-T Recommendation I.150 - 1)B-ISDN asynchronous transfer mode functional characteristics - - ITU-T Recommendation I.363.5 - 1)B-ISDN ATM Adaptation Layer specification: Type 5 AAL - - ITU-T Recommendation Q.2931 - 1)Digital Subscriber Signalling System No. 2 - User-Network Interface (UNI) layer 3 sp
19、ecification for basic call/connection control - - 1)Undated reference. 2)Valid edition at date of issue. BS EN 62365:2009 2 62365 IEC:2009(E) CONTENTS INTRODUCTION.6 1 Scope.8 2 Normative references .8 3 Terms and definitions .8 4 Format of audio data in ATM cells 10 4.1 Format of audio samples .10
20、4.1.1 Subframes.10 4.1.2 Audio sample word 10 4.1.3 Ancillary data 10 4.1.4 Protocol overhead .10 4.2 Packing of sample data into cells 12 4.2.1 Packing schemes 12 4.2.2 Temporal grouping 12 4.2.3 Multi-channel.12 4.2.4 Grouping by channel13 4.3 Formats.13 4.4 ATM adaptation layer 13 4.5 ATM-user-to
21、-ATM-user indication 13 5 Switched virtual circuits 14 5.1 Addresses .14 5.2 Audio call connection: SETUP and ADD PARTY messages .14 5.2.1 Restrictions on connection requests 14 5.2.2 Information elements in the SETUP and ADD PARTY messages .14 5.2.3 Destination response to SETUP and ADD PARTY messa
22、ges.15 5.3 Call disconnection .16 6 Coding of audio formats .16 6.1 Qualifying information16 6.2 Subframe format17 6.3 Packing of subframes into cells .17 6.4 Sampling frequency.18 7 Permanent virtual circuits .18 8 Management interface 19 8.1 Call connection: SETUP messages .19 8.1.1 Restrictions o
23、n connection requests 19 8.1.2 Information elements in the SETUP message 19 8.1.3 Destination response to SETUP message20 8.2 Message encapsulation .20 8.3 Message format and action to be taken by recipient 20 8.4 Message types 21 8.4.1 Messages sent from the controlling entity 21 8.4.2 Messages sen
24、t to the controlling entity23 8.4.3 Vendor-specific messages.25 Annex A (informative) Data protection26 Annex B (informative) Application identifier values.28 BS EN 62365:200962365 IEC:2009(E) 3 Bibliography29 Table 1 Fields contained in a subframe10 Table 2 Default port number and packing for certa
25、in VCIs19 Table 3 Status enquiry message 21 Table 4 Audio connection request message .22 Table 5 Audio disconnection request message.22 Table 6 Input port status message .23 Table 7 Output port status message.24 Table 8 Other status messages25 Table 9 Vendor-specific messages.25 Table A.1 Sequence n
26、umber protection field values.26 Table B.1 Application identifier (octets 9 to 12) values in the BHLI IE 28 BS EN 62365:2009 6 62365 IEC:2009(E) INTRODUCTION This International Standard describes means for the transmission of professional audio across digital networks, including metropolitan- and wi
27、de-area networks, to provide the best performance with regard to latency, jitter, and other relevant factors. Current-generation wide-area communications are based on two very similar systems, synchronous optical network (SONET) and synchronous digital hierarchy (SDH), SONET being used in the United
28、 States and SDH in Europe. On top of them are run integrated services digital network (ISDN), asynchronous transfer mode (ATM), and Internet protocol (IP). ISDN provides telephone call connections of a fixed capacity that carry one 8-bit value per 125 s; when a call is set up, its route through the
29、system is chosen, and the switches that route the data are configured accordingly. Each link, between switches or between switch and end equipment, is formatted into frames that take 125 s to transmit, and each data byte is identified by its position in the frame. ATM, also called broadband ISDN, pr
30、ovides a service similar to ISDN, but with the capacity of each call being specified by the caller. Links are formatted into cells, which consist of a header and 48 data bytes; the header is typically 5 bytes long, and most of it is taken up with the virtual channel identifier (VCI) that shows to wh
31、ich call the cell belongs. Call set-up, routeing, and switching are done in the same way as in ISDN, but with calls not being restricted to 1 byte every 125 s. IP provides a very different service, not designed for continuous media such as audio and video. There is no call set-up, and each packet co
32、ntains enough information within itself to allow it to be routed to its destination. This means that the header is much larger than in the case of ATM, typically 74 bytes, and packets will also typically be much larger, if only because otherwise the overheads would be excessive. Each packet is liabl
33、e to be routed separately, so two packets that are part of the same flow may well take different routes. This can mean that the one that was sent first does not arrive first. For many professional audio applications, a round-trip time from the microphone through the mixing desk and back to the headp
34、hones of no more than 3 ms is required. Allowing 0,5 ms each for conversion from analog to digital and back again, it follows that the network connections to and from the mixing desk must have a latency of less than 1 ms each. For distances of more than about 200 km, the transmission delay alone wil
35、l exceed 1 ms, but within a metropolitan area the transmission delay should be no more than 0,25 ms (equivalent to about 50 km), leaving 0,75 ms for packetization, queuing within switches, and resynchronization within the receiving equipment. Packetization delays are proportional to the size of the
36、transmission unit (frame, cell, or packet), and resynchronization delays depend on how evenly spaced the transmission units are when they arrive at their destination. Both classes of delay are thus small for ISDN and large for IP. Using the format specified in this standard to carry dual-channel IEC
37、 60958-4 audio with a 48 kHz sampling frequency over ATM results in an inter-cell time of 125 s, at which ATM will have similar delays to ISDN. A higher sampling frequency or a larger number of channels would reduce the inter-cell time and hence also the delays. The queuing time within each ISDN swi
38、tch is likely to be around one frame time or 125 s. The ATM documents limit the queuing time in an ATM switch to approximately the inter-cell time for the call, which, as with the other delays, translates into performance similar to that of ISDN for dual-channel 48 kHz IEC 60958-4 audio and better f
39、or higher sampling frequencies or larger numbers of channels. The queuing time within an IP router for normal, best effort, Internet traffic is unbounded, and if the router is congested, packets may simply be thrown away. Resource reservation protocol (RSVP) (see Annex A) allows capacity to be reser
40、ved for a particular traffic flow, but it does BS EN 62365:200962365 IEC:2009(E) 7 not guarantee that the packets will actually be routed over the links on which the capacity has been reserved; if the flow is re-routed, it will only get a best effort service until a reservation has been made on the
41、new route, and it may not even be possible to make a reservation on the new route at all. ATM has therefore been chosen as providing a more convenient service than ISDN and significantly better performance than IP, even when RSVP is used. This standard does not specify a physical interface to the ne
42、twork because one of the features of ATM is its ability to make a seamless connection between interfaces operating at a wide variety of data rates and with different ways of encoding the ATM cells. Commonly used interfaces provide 25,6 Mbit/s over category 3 structured wiring and 155,52 Mbit/s over
43、category-5 structured wiring or fibre-optic cable. The physical layer section description and unique ATM abbreviations can be found in ATM forum approved specifications. See the Bibliography. BS EN 62365:2009 8 62365 IEC:2009(E) DIGITAL AUDIO DIGITAL INPUT-OUTPUT INTERFACING TRANSMISSION OF DIGITAL
44、AUDIO OVER ASYNCHRONOUS TRANSFER MODE (ATM) NETWORKS 1 Scope This International Standard specifies a means to carry multiple channels of audio in linear PCM or IEC 60958-4 format over an ATM layer service conforming to ITU-T Recommendation I.150. It includes a means to convey, between parties, infor
45、mation concerning the digital audio signal when setting up audio calls across the ATM network. It does not specify the physical interface to the network. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the e
46、dition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60958-1, Digital audio interface Part 1: General IEC 60958-4, Digital audio interface Part 4: Professional applications (TA4) ITU-T Recommendation I.150: B-ISDN asynchr
47、onous transfer mode functional characteristics ITU-T Recommendation I.363.5, B-ISDN ATM Adaptation Layer specification: Type 5 AAL ITU-T Recommendation Q.2931: Digital Subscriber Signalling System No. 2 User-Network Interface (UNI) layer 3 specification for basic call/connection control 3 Terms and
48、definitions For the purposes of this document, the following terms and definitions apply. 3.1 asynchronous transfer mode ATM networking technology in which data are carried in 48-o cells NOTE Octet (unit symbol, o) is defined as an 8-bit data element by IEC 60027-2, which is synonymous with byte (un
49、it symbol, B) whenever the term, byte, is restricted to 8-bit elements. 3.2 ATM adaptation layer AAL protocol layer that allows different services, such as packet transfer, to be provided on an ATM network BS EN 62365:200962365 IEC:2009(E) 9 3.3 ATM signaling protocol that conveys connection management and other messages between an ATM network and equipment attached to it 3.4 audio channel path that carries one monophonic digital audio signal 3.5 au
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