1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T L.59 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1 (07/2015) SERIES L: ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS O
2、F OUTSIDE PLANT Optical fibre cables for indoor applications Amendment 1: New appendix on low friction indoor cable and wiring (Japanese experience) Recommendation ITU-T L.59 (2008) Amendment 1 Rec. ITU-T L.59 (2008)/Amd.1 (07/2015) i Recommendation ITU-T L.59 Optical fibre cables for indoor applica
3、tions Amendment 1 New appendix on low friction indoor cable and wiring (Japanese experience) Summary Amendment 1 to Recommendation ITU-T L.59 (2008) provides information on the Japanese experience of low friction indoor cable and wiring. History Edition Recommendation Approval Study Group Unique ID*
4、 1.0 ITU-T L.59 2004-09-06 6 11.1002/1000/7381 2.0 ITU-T L.59 2008-01-08 6 11.1002/1000/9325 2.1 ITU-T L.59 (2008) Amd. 1 2015-07-03 15 11.1002/1000/12578 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations un
5、ique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T L.59 (2008)/Amd.1 (07/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU
6、 Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardiza
7、tion Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups 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 techn
8、ology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with 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. Complian
9、ce with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (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 oblig
10、atory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation
11、 of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position 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 t
12、he date of approval of this Recommendation, ITU had received notice of intellectual property, protected 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 consu
13、lt the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T L.59 (2008)/Amd.1 (07/2015) iii Table of Contents Page 1 Clause 4 1 2) Appendix IV
14、 . 1 Appendix IV Low friction indoor cable and wiring (Japanese experience) . 1 IV.1 Introduction 1 IV.2 Configuration of FTTH for MDUs . 1 IV.3 Problems of conventional wiring 2 IV.4 Conventional indoor cable 3 IV.5 Low friction indoor cable . 3 Rec. ITU-T L.59 (2008)/Amd.1 (07/2015) 1 Recommendati
15、on ITU-T L.59 Optical fibre cables for indoor applications Amendment 1 New appendix on low friction indoor cable and wiring (Japanese experience) 1 Clause 4 Add the following abbreviations in the appropriate alphabetical order. FTTH Fibre To The Home IDF Intermediate Distribution Frame MDF Main Dist
16、ribution Frame MDU Multi Dwelling Unit OLT Optical Line Terminal SP Splitter module Part 2) Appendix IV Add Appendix IV after Appendix III. Appendix IV Low friction indoor cable and wiring (Japanese experience) (This appendix does not form an integral part of this Recommendation.) IV.1 Introduction
17、Low friction indoor cable is widely used for multi dwelling unit (MDU) wiring in Japan. Clauses IV.2 to IV.5 describe the fibre to the home (FTTH) configuration for MDUs, problems of conventional wiring and their solution in Japan. IV.2 Configuration of FTTH for MDUs The basic configuration of the o
18、ptical access network in Japan is shown in Figure IV.1. Two types of topology are employed according to the type of user, namely passive double star or single star topology. (1) For home users, a 4-branch optical splitter module part (SP) is installed in the central office and an 8-branch SP is inst
19、alled on the user side. (2) By contrast, a 32-branch SP (or a combination of one 4-branch SP and four 8-branch SPs) is installed in MDU units such as apartment houses, condominiums and office buildings. As a result, 32 users share an optical line terminal (OLT), and 32 users share a fibre. A configu
20、ration consisting of the single star topology with a media converter is widely used to provide MDUs with FTTH services. For a medium-sized MDU, SPs are installed in a main distribution frame (MDF) and effective wiring approaches involve using a star configuration from an SP installed in an MDF to ea
21、ch unit according to demand as shown in Figure IV.2. This approach makes it easy to manage such operations as a change of service. 2 Rec. ITU-T L.59 (2008)/Amd.1 (07/2015) .L . 5 9 (0 8 )-Amd . 1 (1 5 )_ F I V . 1(1 )O n e-u n i th o me(2 )MD UF TTH fo r M D UONUONUONUF TTHG E -PO NG E -PO NO L T1 :
22、 81 : 3 21 : 4O L TFigure IV.1 Configuration of the optical network L . 5 9 (0 8 )-A md . 1 (1 5 )_ F I V . 2ONUONUONUONUSp l i t t er3 2 SPO p t i cal fi b reMet alFigure IV.2 Topology of wiring inside an MDU IV.3 Problems of conventional wiring Figure IV.3 shows MDF or intermediate distribution fr
23、ame (IDF) boxes and conduits in an existing MDU. Copper facilities have already been installed and the space available for optical fibre wiring is very limited. Moreover, conduits have a small diameter and there are no free conduits. Existing copper cable with a diameter of more than 10 mm is usuall
24、y installed in conduits. However, cable installation is difficult when a conduit is curved, because the cable diameter is large. If optical indoor cable for each unit is required, additional conduits and cabinet boxes would have to be installed due to the lack of space, and this would be both time c
25、onsuming and costly. To expand FTTH to existing MDUs, it was necessary to develop effective wiring techniques for using the free space in existing conduits and the confined space of an MDF. Rec. ITU-T L.59 (2008)/Amd.1 (07/2015) 3 ID FID FID FID FL . 5 9 (0 8 )-Amd . 1 (1 5 )_ F I V . 3M D F / I D F
26、 fo r ca bi nets501P i pes fo r w i ri ng Smal l an d n arro w MD F/ ID F b o x es E x i s t i n g met al l i c faci l i t i esLi m i ted s pa ce fo r o pti ca lca bl e/ ca bi net i ns ta l l a ti o ni n M D U s Smal l p i p es E x i s t i n g co p p er cab l es i n p i p es N o s p are p i p esEx i
27、 s ti ng M D UMD F1 F4 F3 F2 F5 F502 503 504Figure IV.3 Indoor cable wiring problems with existing MDUs IV.4 Conventional indoor cable The most widely used installation method for a conventional indoor cable (hereinafter, conventional cable) in Japan, as shown in Figure IV.4, is described below. 1)
28、Insert a lead wire into a conduit and connect a cable to its head. 2) Pull the lead wire to install the cable and then disconnect it. If a conventional cable is installed with existing copper cables, strong traction-tension is needed to pull it, because of the friction drag imposed by the cable surf
29、ace. When there are several conventional cables, the traction-tension limit means that installation is impracticable. Volatility is high even though a lubricant is applied to the surface of the cable to reduce friction to facilitate cable installation. Moreover, existing cables may be dragged along
30、during installation. In fact, careful attention must be paid to cable installation and removal from a conduit when troubleshooting. L . 5 9 (0 8 )- A md . 1 (1 5 )_ F I V . 42 . 0 m m3 . 1 m mFigure IV.4 Image of conventional cable IV.5 Low friction indoor cable IV.5.1 Functions expected with new ca
31、ble To make it possible to wire all units, three main technical problems have to be overcome. 1) Reducing cable size Installing cables for all units into existing conduit 2) Achieving low cable friction Reducing the traction-tension 4 Rec. ITU-T L.59 (2008)/Amd.1 (07/2015) 3) Adjusting appropriate c
32、able bending rigidity Resistance to buckling when pushing and flexibility for passing through bent parts of the conduit IV.5.2 Design Figure IV.5 shows the small size, low friction and appropriately rigid indoor cable (hereinafter, low friction cable) and Figure IV.6 shows an example of the test met
33、hod setup for the measurement of friction coefficient. The size of its cross-section is about half of that of conventional cable. The friction coefficient is less than 0.25, which is about one-fifth of that of conventional cable. Bending rigidity of low friction cable is about double that of convent
34、ional cable. The friction coefficient of low friction cable is much lower than that of conventional cable to which lubricant has been applied. Furthermore, the friction coefficient of the low friction cable is maintained over time. In addition, the required cable characteristics, which are the same
35、as those of conventional cable, are realized. Figure IV.5 Low friction cable Figure IV.6 Test method setup for the measurement of friction coefficient IV.5.3 Effect of low friction indoor cable The difference in the numbers of conventional and low fiction cable that can be installed is shown in Tabl
36、e IV.1. Three times as many low friction cables can be installed in the space of conventional Rec. ITU-T L.59 (2008)/Amd.1 (07/2015) 5 cables. Thirty low friction cables can be installed in an existing 22 mm conduit with an 8.6 mm copper cable as shown in Figure IV.5. Table IV.1 Numbers of installed
37、 conventional vs. low friction cables Diameter of conduit 16 mm 22 mm 28 mm Conventional cable 4 8 15 Low friction cable 12 30 over 35 NOTE 1 Conventional cable: installed without lubricant. NOTE 2 Copper cable, diameter of 8.6 mm, is already installed. The low friction reduces the pulling tension a
38、nd shortens the installation time. Figure IV.7 presents a comparison of pulling tension and installation time of the low friction cables vs. conventional cables. It is possible to pull the cable with about one-tenth of the usual tension, and also the installation time becomes about one-fifth of the
39、conventional installation time. Additionally, it is possible to remove the low friction cables without disturbing the existing cables, because the low friction characteristics remain. A new installation method is also established that involves pushing the cable into a conduit rather than using a pul
40、ling wire. Figure IV.7 shows that the installation time is reduced by about one-third compared with the conventional method, when the conduit condition is good. This is because the conventional method requires two steps, whereas the new insertion method requires only one. In addition, the pushing me
41、thod may make it possible to insert a cable into a conduit that has sustained damage, such as a dented portion that is preventing the insertion of a new cable. There are cases where it is impossible to insert a new cable into an existing conduit with the conventional method. However, it is possible
42、with the new method. L . 5 9 (0 8 )-A md . 1 (1 5 )_ F I V . 71 4 7 10 13 16 19(Ca b l e n u mb ers )050100150200250050100150200250300350400(Sec)InstallationtimePulling/Pushingtension(N)Co n v en t i o n al cab l e (p u l l i n g t en s i o n )L o w fri ct i o n cab l e (p u l l i n g t en s i o n )
43、Co n v en t i o n al cab l e (i n s t al l at i o n t i me: p u l l i n g )L o w fri ct i o n cab l e (i n s t al l at i o n t i me: p u l l i n g )L o w fri ct i o n cab l e (i n s t al l at i o n t i me: p u s h i n g )Figure IV.7 Installation results examples of conventional cable and low frictio
44、n cable in a 22 mm conduit Printed in Switzerland Geneva, 2015 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunica
45、tion services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection agains
46、t interference Series L Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant Series M Telecommunication management, including TMN and network maintenance Series N Maintenance: international sound pro
47、gramme and television transmission circuits Series O Specifications of measuring equipment Series P Terminals and subjective and objective assessment methods Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telema
48、tic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
