1、 International Telecommunication Union ITU-T L.76TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (05/2008) SERIES L: CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT Copper loop requirements for various technologies including indoor and structured cabling Recom
2、mendation ITU-T L.76 Rec. ITU-T L.76 (05/2008) i Recommendation ITU-T L.76 Copper loop requirements for various technologies including indoor and structured cabling Summary Old indoor installations, designed for voice transmission, are responsible for intermittent faults and performance degradation,
3、 in terms of throughput, when they are used for broadband applications. Very often, the use of older cabling becomes impractical for todays needs. Structured cabling is a solution that allows reliable broadband transmission and accommodates the increasingly varied information and communication servi
4、ces, such as super-high speed internet, video-communication, voice over Internet protocol (VoIP), Video on Demand (VoD), Internet protocol television (IPTV), security, telemetry, etc. General customer premises and residential buildings cabling architectures are introduced. Pertinent electrical param
5、eters and requirements are referred to in ISO/IEC 11801 and ITU-T L.75. The purposes of Recommendation ITU-T L.76 are: to present general indoor network architectures; to recommend structured cabling as a solution for indoor network implementations; and to define the requirements to indoor copper ne
6、tworks. Source Recommendation ITU-T L.76 was approved on 29 May 2008 by ITU-T Study Group 6 (2005-2008) under Recommendation ITU-T A.8 procedure. Keywords General customer premises and residential buildings cabling, indoor copper cabling requirements, structured cabling. ii Rec. ITU-T L.76 (05/2008)
7、 FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for stu
8、dying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study gro
9、ups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with
10、ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisi
11、ons (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such
12、words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position
13、concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected
14、by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2009 All rights reserved. No part of thi
15、s publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T L.76 (05/2008) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 1 4 Abbreviations and acronyms 2 5 Conventions 3 6 Generic cabling system for customer premises 3 6.1 Structure o
16、f generic cabling for building telecommunication facilities . 3 6.2 Campus backbone cabling subsystem 3 6.3 Building backbone cabling subsystem . 3 6.4 Horizontal cabling subsystem. 3 6.5 Design objectives 4 7 Residential area telecommunication cabling 4 7.1 Principles 4 7.2 Multi-tenant unit/apartm
17、ent cabling system. 4 7.3 Single residential unit cabling system 5 8 Requirements 6 8.1 Performance of balanced cabling . 6 Bibliography. 8 Rec. ITU-T L.76 (05/2008) 1 Recommendation ITU-T L.76 Copper loop requirements for various technologies including indoor and structured cabling 1 Scope The purp
18、oses of this Recommendation are: to present general indoor network architectures; to recommend structured cabling as a solution for indoor network implementations; and to define the requirements for indoor copper networks. 2 References The following ITU-T Recommendations and other references contain
19、 provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the p
20、ossibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Rec
21、ommendation. ITU-T L.75 Recommendation ITU-T L.75 (2008), Test, acceptance and maintenance methods of copper subscriber pairs. ISO/IEC 11801 ISO/IEC 11801:2002, Information technology Generic cabling for customer premises. 3 Definitions This Recommendation defines the following terms (aligned with I
22、SO/IEC 11801): 3.1 balanced cable: Cable consisting of one or more metallic symmetrical cable elements (twisted pairs or quads). 3.2 building backbone cabling subsystem: Distribution system connecting the main distribution frame to an intermediate distribution frame, an intermediate distribution box
23、, a floor distribution frame or a floor distribution box in a building and the distribution system interconnecting intermediate distribution frames in a building. 3.3 building distribution frame (or box): Distribution frame (or box) installed in each multi-tenant unit for effective building wire man
24、agement in case of a configuration of a residential complex of more than two multi-tenant units. 3.4 cabling: System of telecommunication cables, cords and connecting hardware that can support the connection of information technology equipment. 3.5 campus: Premise containing one or more buildings. 3
25、.6 campus backbone cabling subsystem: Distribution system connecting the main distribution frame or the main distribution box in a local area to a building distribution frame or a building distribution box, and the distribution system interconnecting building distribution frames. 3.7 consolidation p
26、oint (CP): Connection point in the horizontal cabling subsystem between a floor distributor and a telecommunications outlet. 2 Rec. ITU-T L.76 (05/2008) 3.8 connecting hardware: Connecting hardware is considered to consist of a device or a combination of devices used to connect cables or cable eleme
27、nts. 3.9 cross-connect: Apparatus enabling the termination of cable elements and their cross-connection, primarily by means of patch cords or jumpers. 3.10 customer device box: Distribution box installed in a private space of a user for effective distribution of telecommunication line or the line fo
28、r cable television facilities, etc. 3.11 demarcation point: Boundary point between a commercial facility and user facility. 3.12 main distribution box: Network connection facility which interconnects a carriers facility with a users facility in a small building which accommodates below 300 office li
29、nes, as in a single residential unit, and which is installed at a demarcation point for satisfactory cross-connection and maintenance of the line. 3.13 main distribution frame: Network connection facility which interconnects a carriers facility with a users facility in a big building which accommoda
30、tes over 300 office lines, as in a multi-tenant unit, and which is installed instead of a main distribution box at a demarcation point for satisfactory cross-connection and maintenance of the line. 3.14 patch cord: Cable, cable unit or cable element with connector(s) used to establish connections on
31、 a patch panel. 3.15 patch panel: Assembly of multiple connectors designed to accommodate the use of patch cords. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: ACR Attenuation to Crosstalk Ratio BD Building Distributor CD Campus Distributor CP Consol
32、idation Point DSLAM Digital Subscriber Line Access Multiplexer EQP Equipment ELFEXT Equal Level Far-End CrossTalk FD Floor Distributor FEXT Far-End CrossTalk IPTV Internet Protocol Television NEXT Near-End CrossTalk PS ELFEXT Power Sum Equal Level Far-End CrossTalk PS NEXT Power Sum Near-End CrossTa
33、lk TO Telecommunication Outlet UTP Unshielded Twisted Pair VoD Video on Demand VoIP Voice over Internet Protocol xDSL Generic Digital Subscriber Line Rec. ITU-T L.76 (05/2008) 3 5 Conventions None. 6 Generic cabling system for customer premises 6.1 Structure of generic cabling for building telecommu
34、nication facilities Generic cabling systems contain up to three cabling subsystems: campus backbone, building backbone and horizontal cabling. The cabling subsystems are connected together to create a generic cabling system with a structure as shown in Figure 6-1. The distributors provide the means
35、to configure the cabling to support different topologies such as bus, star and ring. In case of a hierarchical structure of the interconnection of subsystems, refer to ISO/IEC 11801. Figure 6-1 General cabling structure 6.2 Campus backbone cabling subsystem The campus backbone cabling subsystem exte
36、nds from the campus distributor (CD) to the building distributor(s) (BD), usually located in separate buildings. When present, the subsystem includes the campus backbone cables, any cabling components within the building entrance facilities, jumpers and patch cords in the campus distributor, and the
37、 connecting hardware on which the campus backbone cables are terminated (at both the campus and building distributors). 6.3 Building backbone cabling subsystem The building backbone cabling subsystem extends from building distributor(s) to the floor distributor(s) (FD). When present, the subsystem i
38、ncludes the building backbone cables, jumpers and patch cords in the building distributor, and the connecting hardware on which the building backbone cables are terminated (at both the building and floor distributors). 6.4 Horizontal cabling subsystem The horizontal cabling subsystem extends from a
39、floor distributor to the telecommunication outlet(s) connected to it. The subsystem includes the horizontal cables, jumpers and patch cords in the floor distributor, the mechanical termination of the horizontal cables at the telecommunication outlet, the mechanical termination of the horizontal cabl
40、es at the floor distributor including the connecting hardware, a consolidation point (optional) and the telecommunication outlets. 4 Rec. ITU-T L.76 (05/2008) 6.5 Design objectives Horizontal cabling should be designed to support the broadcast set of existing and emerging applications and therefore
41、provide the longest operational life. This will minimize disruption and the high cost of re-cabling in the work area. Building backbone cabling should be designed for the entire life of the generic cabling system. However, it is common to adopt short-term approaches that support current and foreseea
42、ble application requirements, particularly where there is no good physical access to pathways. The selection of campus backbone cabling may require a longer-term approach than that adopted for the building backbone, particularly if access to pathways is more limited. 7 Residential area telecommunica
43、tion cabling 7.1 Principles In case of a multi-tenant unit, a customer device box for each household or a connection point with the function of a customer device box should be installed in each users private space. In case of a single residential area unit, a customer device box should be installed
44、at a demarcation point instead of a main distribution box. At least more than one telecommunication outlet should be installed from a customer device box to each room, and four pairs of UTP cables or equivalent to that or more should be installed in star wiring topology from a customer device box to
45、 each telecommunication outlet. However, a voice-only service is an exception and does not follow this principle. In lead-in line for each household, UTP cable with at least more than four pairs should be led in, and more than eight pairs is recommended. Cabling in a building should be done using th
46、e star wiring topology, and careful consideration for installation of building telecommunication facilities should be made when designing so that it can accommodate various information and communication services permanently. 7.2 Multi-tenant unit/apartment cabling system At a demarcation point, the
47、main distribution box or the main distribution frame is installed as user network connection equipment. The section from the main distribution box or the main distribution frame to a building distribution frame is called the campus backbone cabling subsystem, and the section from a building distribu
48、tion frame to an intermediate distribution frame is called the building backbone cabling subsystem, and the section from an intermediate distribution frame to a customer device box, or the telecommunication outlet, is called the horizontal cabling subsystem. In a case where a residential complex of
49、over two multi-tenant units are configured, the main distribution box is installed in any one place within the multi-tenant unit, and then the office line is led in. Backbone cables are distributed to each customer device box of other multi-tenant units through a building distribution frame (a building distribution box) or an intermediate distribution frame. Cabling equipment and material for each building cabling subsystem are selected in consideration of building usage, telecommunication accommodation facilities, application faci
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