1、 International Telecommunication Union ITU-T G.996.2TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 4(08/2013) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Metallic access networks Single-ended line testing for digital subs
2、criber lines (DSL) Amendment 4: Updates to Annex E Recommendation ITU-T G.996.2 (2009) Amendment 4 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CA
3、RRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATIO
4、N OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 General G.900G.909 Parameters for optical fibre cable systems G.9
5、10G.919 Digital sections at hierarchical bit rates based on a bit rate of 2048 kbit/s G.920G.929 Digital line transmission systems on cable at non-hierarchical bit rates G.930G.939 Digital line systems provided by FDM transmission bearers G.940G.949 Digital line systems G.950G.959 Digital section an
6、d digital transmission systems for customer access to ISDN G.960G.969 Optical fibre submarine cable systems G.970G.979 Optical line systems for local and access networks G.980G.989 Metallic access networks G.990G.999MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.100
7、0G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.996.2 (2009)/Amd.4 (08/2013) i Recomme
8、ndation ITU-T G.996.2 Single-ended line testing for digital subscriber lines (DSL) Amendment 4: Updates to Annex E Summary Amendment 4 to Recommendation ITU-T G.996.2 (2009) provides the following updates to Annex E: accuracy values for multi-component 4-element resistance and 3-element capacitance
9、parameters in MELT-PMD a definition on dealing with the xDSL input capacitance during measurements. History Edition Recommendation Approval Study Group Unique ID11.0 ITU-T G.996.2 2009-05-22 15 11.1002/1000/9666-en 1.1 ITU-T G.996.2 (2009) Amd. 1 2009-10-09 15 11.1002/1000/9892-en 1.2 ITU-T G.996.2
10、(2009) Amd. 2 2012-04-06 15 11.1002/1000/11503-en1.3 ITU-T G.996.2 (2009) Amd. 3 2013-03-16 15 11.1002/1000/11892-en1.4 ITU-T G.996.2 (2009) Amd. 4 2013-08-29 15 11.1002/1000/11995-en_ 1To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followe
11、d by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T G.996.2 (2009)/Amd.4 (08/2013) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communicatio
12、n technologies (ICTs). The ITU 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
13、 Telecommunication Standardization 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 s
14、ome areas of information technology 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 recogni
15、zed operating agency. Compliance 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 wor
16、ds “shall“ or some other obligatory 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 RIGHTS ITU draws attention to the possibility that
17、 the practice or implementation 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 Recommendati
18、on development process. As of the 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 th
19、erefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2014 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 G.996.2 (2009)/Amd.4 (08/2013) 1 Recommendation ITU
20、-T G.996.2 Single-ended line testing for digital subscriber lines (DSL) Amendment 4: Updates to Annex E 1) Update to Annex E Specific requirements for a MELT-PMD Add the following new paragraph to the end of clause E.1: The accuracy values provided in this annex are based on an assumption that the M
21、ELT functionality has, or obtains, the value of the input capacitance looking into the xTU-C and subtracts it from the raw results to report the measurement of the external capacitance. The method to obtain the input capacitance of the xTU-C is vendor discretionary and is beyond the scope of this Re
22、commendation. No part of the overall accuracy budget has been allocated to account for a possible change in the input capacitance of the xTU-C. Add a new clause E.1.1.12 as follows: E.1.1.12 Combined measurement of 4-element resistance and 3-element capacitance The accuracy numbers defined in clause
23、s E.1.1.1.1 and E.1.1.2 apply to a 4-element DC resistance and a 3-element capacitance measurement performed on a single component. This clause defines the accuracy numbers for a combined measurement performed on a multiple component network as shown in Figure E.3. The network consists of six compon
24、ents located tip-to-ring, tip-to-ground and ring-to-ground, with neither foreign voltages nor a signature network connected to it. G.996.2(09)-Amd.4(13)_FE.3RINGCRGRRGTIPCTRCTGRor RTR RTRTGFigure E.3 Multiple component network The accuracy numbers included in Tables E.11.8 to E.11.12 are applicable
25、to a combined measurement of 4-element DC resistance and 3-element capacitance when using any combination of external components selected within the range of values defined in Table E.11.6 or in Table E.11.7. Tables E.11.8 to E.11.12, indicating the accuracy of individual components when 2 Rec. ITU-
26、T G.996.2 (2009)/Amd.4 (08/2013) measured within a multi-component network, shall not be used for components outside of the range covered by Tables E.11.6 and E.11.7. Table E.11.6 Range of external componentsfor MELT measurements on ADSLplus or VSDL equipment Resistance range: 1 M to 6.8 M CTGand CR
27、Gcapacitance range: 22 nF to 470 nF CTRcapacitance range: 10 nF to 100 nF Table E.11.7 Range of external components for MELT measurements on SHDSL equipment Resistance range: 1 M to 6.8 M CTGand CRGcapacitance range: 22 nF to 470 nF CTRcapacitance range: 100 nF to 1 F Tables E.11.8 to E.11.12 provid
28、e the accuracy of individual components when measured within a multi-component network. Those accuracy figures are applicable when all components have values selected within the ranges specified in Table E.11.6 for ADSL2plus or VDSL applications, or specified in Table E.11.7 for SHDSL applications.
29、The accuracies are cumulative when both an absolute and a relative figure are provided. The 7-element parameter set, that is the four DC resistances (RTR, RRT, RTGand RRG) and the three capacitances (CTR, CTGand CRG), shall be measured and reported. Table E.11.8 Resistance accuracy RTR, RTG,RRGResis
30、tance range Accuracy 1 M-4 M 15% 4 M-5 M 20% 5 M-6.8 M 25% Table E.11.9 Capacitance accuracy CTRfor MELT measurements on ADSLplus or VSDL equipment Capacitance range Accuracy 10 nF-60 nF 7 nF 60 nF-100 nF (4 nF + 5%) Rec. ITU-T G.996.2 (2009)/Amd.4 (08/2013) 3 Table E.11.10 Capacitance accuracy CTG,
31、 CRGfor MELT measurements on ADSLplus or VSDL equipment Capacitance range Accuracy 22 nF-60 nF 6 nF 60 nF-300 nF (3 nF + 5%) 300 nF-470 nF 6% Table E.11.11 Capacitance accuracy CTRfor MELT measurements on SHDSL equipmentCapacitance range Accuracy 100 nF-700 nF 55 nF 700 nF-1 F (20 nF + 5%) Table E.1
32、1.12 Capacitance accuracy CTG, CRGfor MELT measurements on SHDSL equipment Capacitance range Accuracy 22 nF-250 nF 25 nF 250 nF-470 nF (15 nF + 4%) Printed in Switzerland Geneva, 2014 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General tariff principles Series
33、 E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series
34、 J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M Telecommunication management, including TMN and network ma
35、intenance Series N Maintenance: international sound programme 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 se
36、rvices terminal equipment Series T Terminals for telematic 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
