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1、BRITISH STANDARD BS EN 62365:2005 Digital audio Digital input-output interfacing Transmission of digital audio over asynchronous transfer mode (ATM) networks The European Standard EN 62365:2005 has the status of a British Standard ICS 35.200; 33.160 ? Licensed Copy: sheffieldun sheffieldun, na, Mon
2、Nov 13 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 62365:2005 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 24 January 2006 BSI 24 January 2006 ISBN 0 580 47522 0 National foreword This British Standard is the official English
3、 language version of EN 62365:2005. It is identical with IEC 62365:2004. The UK participation in its preparation was entrusted to Technical Committee EPL/100, Audio, video and multimedia systems and equipment, which has the responsibility to: A list of organizations represented on this committee can
4、 be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” f
5、acility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligat
6、ions. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of page
7、s This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 29 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy: sheffieldun she
8、ffieldun, na, Mon Nov 13 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD EN 62365 NORME EUROPENNE EUROPISCHE NORM September 2005 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnis
9、che Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2005 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 62365:2005 E ICS 35.200; 33.160 English version Digital audio Digital input-output interfacing Transmissio
10、n of digital audio over asynchronous transfer mode (ATM) networks (IEC 62365:2004) Audionumrique Interface numrique dentre-sortie Transmission de laudionumrique sur les rseaux mode de transfert asynchrone (ATM) (CEI 62365:2004) Digitalton Digitale Ein-/Ausgangsschnittstellen bertragung von Digitalto
11、n ber ATM-Netzwerke (IEC 62365:2004) This European Standard was approved by CENELEC on 2005-08-01. CENELEC 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.
12、Up-to-date lists and bibliographical references concerning such national standards may be obtained on application 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 translati
13、on under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Ger
14、many, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2
15、 Foreword The text of the International Standard IEC 62365:2004, prepared by IEC TC 100, Audio, video and multimedia systems and equipment, was submitted to the formal vote and was approved by CENELEC as EN 62365 on 2005-08-01 without any modification. The following dates were fixed: latest date by
16、which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2006-08-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2008-08-01 Annex ZA has been added by CENELEC. _ Endorsement notice
17、The text of the International Standard IEC 62365:2004 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following note has to be added for the standard indicated: IEC 60027-2 NOTE Harmonized as HD 60027-2:2003 (not modified). _ EN
18、 62365:2005 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 3 EN 62365:2005 CONTENTS INTRODUCTION.4 1 Scope 6 2 Normative references .6 3 Terms and definitions .6 4 Format of audio data in ATM cells.7 4.1 Format of audio samples7 4.2 Packing
19、 of sample data into cells .10 4.3 Formats.11 4.4 ATM adaptation layer.11 4.5 ATM-user-to-ATM-user indication.12 5 Switched virtual circuits 12 5.1 Addresses .12 5.2 Audio call connection: SETUP and ADD PARTY messages.12 5.3 Call disconnection .14 6 Coding of audio formats15 6.1 Qualifying informati
20、on15 6.2 Subframe format15 6.3 Packing of subframes into cells16 6.4 Sampling frequency.16 7 Permanent virtual circuits .17 8 Management interface 17 8.1 Call connection: SETUP messages .17 8.2 Message encapsulation .19 8.3 Message format and action to be taken by recipient .19 8.4 Message types 19
21、Annex A (informative) Data protection 25 Annex B (informative) Application identifier values27 Annex ZA (normative) Normative references to international publications with their corresponding European publications29 Bibliography .28 Table 1 Fields contained in a subframe 8 Table 2 Combinations of su
22、bframe format and packing scheme 11 Table 3 Default port number and packing for certain VCIs.17 Table 4 Status enquiry message 20 Table 5 Audio connection request message20 Table 6 Audio disconnection request message .21 Table 7 Input port status message 22 Table 8 Output port status message 23 Tabl
23、e 9 Other status messages24 Table 10 Vendor-specific messages .24 Table A.1 Sequence number protection field values25 Table B.1 Application identifier (octets 9 to 12) values in the BHLI IE. .27 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BS
24、I EN 62365:2005 4 INTRODUCTION This International Standard describes means for the transmission of professional audio across digital networks, including metropolitan- and wide-area networks, to provide the best performance with regard to latency, jitter, and other relevant factors. Current-generatio
25、n 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 States and SDH in Europe. On top of them are run integrated services digital network (ISDN), asynchronous transfer mode (ATM),
26、 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 system is chosen, and the switches that route the data are configured accordingly. Each link, between switches or between switc
27、h 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, provides a service similar to ISDN, but with the capacity of each call being specified by the caller. Links are formatted into ce
28、lls, 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 which call the cell belongs. Call set-up, routeing, and switching are done in the same way as in ISDN, but with calls not being r
29、estricted 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 contains enough information within itself to allow it to be routed to its destination. This means that the header is much larger
30、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 liable to be routed separately, so two packets that are part of the same flow may well take different routes. This can mean that the
31、 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 headphones of no more than 3 ms is required. Allowing 0,5 ms each for conversion from analog to digital and back again, it follows t
32、hat 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 will exceed 1 ms, but within a metropolitan area the transmission delay should be no more than 0,25 ms (equivalent to about 50 km)
33、, leaving 0,75 ms for packetization, queuing within switches, and resynchronization within the receiving equipment. Packetization delays are proportional to the size of the transmission unit (frame, cell, or packet), and resynchronization delays depend on how evenly spaced the transmission units are
34、 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 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
35、 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 switch is likely to be around one frame time or 125 s. The ATM documents limit the queuing time in an ATM switch to approximately
36、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 for higher sampling frequencies or larger numbers of channels. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 12:51:34 G
37、MT+00:00 2006, Uncontrolled Copy, (c) BSI 5 EN 62365:2005 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 reserved
38、for a particular traffic flow, but it does 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 new route, and it may not even be possib
39、le 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 network because one of the features of ATM
40、 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 category-5 structured wiring or fibre-op
41、tic cable. The physical layer section description and unique ATM abbreviations can be found in ATM forum approved specifications. See the Bibliography. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 62365:2005 6 DIGITAL AUDIO DIGITAL INP
42、UT-OUTPUT INTERFACING TRANSMISSION OF DIGITAL 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 incl
43、udes a means to convey, between parties, information 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 t
44、his document. For dated references, only the edition 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 IT
45、U-T Recommendation I.150: B-ISDN asynchronous 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 ba
46、sic call/connection control 3 Terms and 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
47、60027-2, which is synonymous with byte (unit 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 3.3 ATM signaling protocol that conveys connection
48、 management and other messages between an ATM network and equipment attached to it Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 7 EN 62365:2005 3.4 audio channel path that carries one monophonic digital audio signal 3.5 audio port physica
49、l or virtual connector that carries a fixed number of audio channels 3.6 information element (IE) component of an ATM signalling message 3.7 MADI serial multi-channel audio digital interface 3.8 organizationally unique identifier (OUI) 3-o code issued by a designated agency to form globally consistent bit strings as described in OUI and company_id assignments 3.9 user-to-user indicatio