1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T L.60TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (09/2004) SERIES L: CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT Construction of optical/metallic hybrid cables ITU-T Recommendation L.60 ITU-T Rec. L.60 (09/20
2、04) i ITU-T Recommendation L.60 Construction of optical/metallic hybrid cables Summary An optical/metallic hybrid cable is a cable which contains both optical fibres and metallic wires for telecommunication and/or power feeding. Firstly, this Recommendation describes cable construction and secondly
3、keynotes to the use of this type of cable are provided. Technical requirements may differ according to the installation environment. Environmental issues and test methods for cable characteristics are described in other L-series Recommendations. Source ITU-T Recommendation L.60 was approved on 6 Sep
4、tember 2004 by ITU-T Study Group 6 (2001-2004) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. L.60 (09/2004) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Se
5、ctor (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 Standardization Assembly (WTSA), which meets eve
6、ry 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 technology which fall within ITU-Ts purvie
7、w, 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. Compliance with this Recommendation is volunt
8、ary. 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 obligatory language such as “must“ and the n
9、egative 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 RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve th
10、e 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 the date of approval of this Recommenda
11、tion, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 20
12、04 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. L.60 (09/2004) iii CONTENTS Page 1 Scope 1 2 References. 1 2.1 Normative references 1 2.2 Informative reference . 2 3 Terms and definitions . 2 4 Ab
13、breviations 2 5 Optical/metallic hybrid cable construction. 2 5.1 Characteristics of each media. 3 5.2 Cable element . 3 5.3 Mechanical characteristics 4 5.4 Environmental conditions. 4 6 Test methods. 4 Appendix I Chinese experience 5 I.1 Cable design . 5 ITU-T Rec. L.60 (09/2004) 1 ITU-T Recommend
14、ation L.60 Construction of optical/metallic hybrid cables 1 Scope This Recommendation refers to cables containing both optical fibres and metallic wires and: Deals with construction of optical/metallic hybrid cables. The optical fibre dimensional and transmission characteristics, together with their
15、 test methods, should comply with ITU-T Recs G.652, G.653, G.654, G.655, G.656 and IEC 60793-2-10. Dimensional and transmission characteristics of metallic wires for telecommunication, together with their test methods, should comply with ITU-T Rec. L.1 and other L-series Recommendations; Deals with
16、keynotes for the use of optical/metallic hybrid cables; Recommends that an optical/metallic hybrid cable should be provided with cable-end sealing and protection during cable delivery and storage, as is usual for metallic and/or optical cables. If splicing components have been factory installed they
17、 should be adequately protected; Recommends that pulling devices can be fitted to the end of the cable if required. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the tim
18、e 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 possibility of applying the most recent edition of the Recommendations and other references listed below. A
19、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 Recommendation. 2.1 Normative references ITU-T Recommendation G.650.1 (2004), Definitions and test methods for
20、 linear, deterministic attributes of single-mode fibre and cable. ITU-T Recommendation G.650.2 (2002), Definitions and test methods for statistical and non-linear related attributes of single-mode fibre and cable. ITU-T Recommendation G.652 (2003), Characteristics of a single-mode optical fibre and
21、cable. ITU-T Recommendation G.653 (2003), Characteristics of a dispersion-shifted single-mode optical fibre and cable. ITU-T Recommendation G.654 (2004), Characteristics of a cut-off shifted single-mode optical fibre and cable. ITU-T Recommendation G.655 (2003), Characteristics of a non-zero dipersi
22、on-shifted single-mode optical fibre and cable. ITU-T Recommendation G.656 (2004), Characteristics of a fibre and cable with non-zero dispersion for wideband optical transport. ITU-T Recommendation L.1 (1988), Construction, installation and protection of telecommunication cables in public networks.
23、ITU-T Recommendation L.10 (2002), Optical fibre cables for duct and tunnel application. 2 ITU-T Rec. L.60 (09/2004) ITU-T Recommendation L.26 (2002), Optical fibre cables for aerial application. ITU-T Recommendation L.43 (2002), Optical fibre cables for buried application. ITU-T Recommendation L.59
24、(2004), Optical fibre cables for indoor application. IEC 60227 (2003), Polyvinyl chloride insulated cables of rated voltages up to and including 450/750 V. IEC 60228 (2004), Conductors of insulated cables. IEC 60793-2-10 (2004), Optical fibres Part 2-10: Product specifications Sectional specificatio
25、n for category A1 multimode fibres. IEC 61156-2-1 (2003), Multicore and symmetrical pair/quad cables for digital communications Part 2-1: Horizontal floor wiring Blank detail specification. 2.2 Informative reference ITU-T Handbook (1994), Construction, Installation, Jointing and Protection of Optica
26、l Fibre Cables. 3 Terms and definitions For the purpose of this Recommendation, the definitions given in ITU-T Recs G.650.1, and G.650.2 apply. 4 Abbreviations This Recommendation uses the following abbreviations: FRP Fibre Reinforced Plastic FTTC Fibre-To-The-Curb FTTH Fibre-To-The-Home PE PolyEthy
27、lene PVC PolyVinylChloride 5 Optical/metallic hybrid cable construction This Recommendation deals with three types of optical/metallic hybrid cables as shown in Table 1. Table 1/L.60 Contents of each cable type Cable type Optical fibres Metallic wires for telecommunication Metallic wires for power f
28、eeding Type-I Contained Contained No Type-II Contained No Contained Type-III Contained Contained Contained Type-I can be used for optical transmission and electric transmission carrying analog and/or digital signals. Type-II can be used for optical transmission and power feeding. Type-III can be use
29、d for optical transmission, electric transmission carrying analog and/or digital signals and power feeding. There are two major methods to contain those media in a cable. One method is to strand each medium fabricated cylindrically (with or without other materials) around a central member. The other
30、 is to insert media into slots of a slotted core as described in 5.2.4. ITU-T Rec. L.60 (09/2004) 3 5.1 Characteristics of each media 5.1.1 Optical fibre Optical fibres described in ITU-T Recs G.652, G.653, G.654, G.655, G.656 and IEC 60793-2-10 should be used, depending upon circumstances and techn
31、ical requirements. 5.1.2 Symmetrical metallic pair The electrical characteristics of a symmetrical pair or pairs should meet with those agreed upon between a manufacturer and a user. The following items should be agreed upon: maximum conductor direct current resistance; maximum conductor direct curr
32、ent resistance unbalance of the pair; mutual capacitance; capacitance unbalance; attenuation (insertion loss); near-end crosstalk (NEXT); power sum of near-end crosstalk (PSNEXT); far-end crosstalk (FEXT); equal level of far-end crosstalk (ELFEXT); insulation resistance; other parameters which will
33、be agreed upon between a manufacturer and a user. The mechanical and the environmental characteristics should comply with IEC 61156-2-1 unless there is a different agreement between a manufacturer and a user. 5.1.3 Power feeding wires The conductor characteristics of the copper wire should comply wi
34、th IEC 60228, unless there is a different agreement between a manufacturer and a user. The insulation characteristic of the copper wire should be in accordance with IEC 60227 criterion requirements, unless there is a different agreement between a manufacturer and a user. 5.2 Cable element The make-u
35、p of the cable core, in particular the number of fibres, their method of protection and identification, the location of strength members and metallic wires or pairs, if required, should be clearly defined. 5.2.1 Loose tube A loose tube construction is frequently used for protecting and gathering opt
36、ical fibres and/or ribbon fibres. Filling material may be contained in the tube. 5.2.2 Symmetrical pair unit A symmetrical pair unit contains stranded copper pairs. It is fabricated cylindrically with or without additional suitable material. Its diameter is similar to that of a loose tube. 5.2.3 Pow
37、er feeding wire unit A power feeding wire unit contains power-feeding wire(s) and is fabricated cylindrically with or without suitable material in order to have a diameter similar to that of a loose tube. 4 ITU-T Rec. L.60 (09/2004) 5.2.4 Slotted core In order to avoid direct pressure on optical fib
38、res from the outside of the cable, optical fibres and/or ribbon fibres may be located into slots. Usually, slots are provided in a helical or SZ configuration stranded around a cylindrical rod. The slotted core usually contains a strength member (metallic or non-metallic). The strength member shall
39、adhere tightly to the slotted core in order to obtain temperature stability and avoid separation when a pulling force is applied during installation. 5.2.5 Strength member The cable should be designed with strength members suitable to meet installation and service conditions so that the fibres are n
40、ot subjected to strain levels in excess of those agreed upon between a manufacturer and a user. The strength member(s) may be either metallic or non-metallic. 5.2.6 Water blocking material Filling a cable with water-blocking material, or wrapping the cable core with layers of water swellable materia
41、l, are two means of protecting the fibres from water ingress. A water-blocking element (tapes, filling compound, water swelling powder or combination of materials) may be used. Any materials used should not be harmful to personnel. The materials in the cable should be compatible with each other and,
42、 in particular, should not adversely affect the fibre characteristics. These materials shall not hinder splicing and/or connection operations. 5.2.7 Sheath The cable core shall be covered with a sheath or sheaths suitable for environmental and mechanical conditions associated with storage, installat
43、ion and operation. The sheath may be of a composite construction and may include strength members. Sheath considerations for optical fibre cables are generally the same as for metallic conductor cables. Consideration should also be given to the amount of hydrogen generated from a metallic moisture b
44、arrier. The minimum acceptable thickness of the sheath should be stated, together with any maximum and minimum allowable overall cable diameter. Selection of sheath material is one of the important issues to be considered in order, for example, to satisfy fire safety requirements. Polyethylene is wi
45、dely used as cable sheath material but may not be suitable for indoor cables for fire safety reasons. 5.3 Mechanical characteristics Unless there is a different agreement between a manufacturer and a user, an optical/metallic hybrid cable should have mechanical characteristics which are described in
46、 ITU-T Recs L.10, L.26, L.43 or L.59 depending upon the installation environment. 5.4 Environmental conditions Unless there is a different agreement between a manufacturer and a user, an optical/metallic hybrid cable should meet environmental conditions which are described in ITU-T Recs L.10, L.26,
47、L.43 or L.59 depending upon the installation environment. 6 Test methods Unless there is a different agreement between a manufacturer and a user, an optical/metallic hybrid cable should be tested with the test methods which are described in ITU-T Recs L.10, L.26, L.43 or L.59 depending upon the inst
48、allation environment. ITU-T Rec. L.60 (09/2004) 5 Appendix I Chinese experience Introduction Optical fibre cables used in the access network must be suitable for network topologies such as FTTH and FTTC. Optical/Metallic hybrid cable applies not only to the optical signals, but also to the digital s
49、ignals to be transmitted and to the power needed to feed active equipment. This contribution presents three types of optical fibre/stranded copper hybrid cables used in different access network application environments. Each type has been successfully installed in the access network in China. DTTCableFigure I.1/L.60 The 3-dimensional sketch map of the optical fibre/copper hybrid cable The cable types are: Optical fibre/symmetrical pair hybrid cable for optical/data signal transmission. Optical fibre/stranded cop
