1、 TECHNICAL REQUIREMENT T1.TRQ.7-2002 Technical Requirement for Non-Loaded Metallic Loops Supporting Basic Voicegrade Services Prepared by T1E1.3 Working Group on Optical and Electrical Access Problem Solvers to the Telecommunications Industry A Word from ATIS and Committee T1 Established in February
2、 1984, Committee T1 develops technical standards, reports and requirements regarding interoperability of telecommunications networks at interfaces with end-user systems, carriers, information and enhanced-service providers, and customer premises equipment (CPE). Committee T1 is sponsored by ATIS and
3、 is accredited by ANSI. T1.TRQ.7-2002 Published by Alliance for Telecommunications Industry Solutions 1200 G Street, NW, Suite 500 Washington, DC 20005 Committee T1 is sponsored by the Alliance for Telecommunications Industry Solutions (ATIS) and accredited by the American National Standards Institu
4、te (ANSI). Copyright 2002 by Alliance for Telecommunications Industry Solutions All rights reserved. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. For information contact ATIS at 202.6
5、28.6380. ATIS is online at . Printed in the United States of America. T1.TRQ.7-2002 Technical Requirements for Non-Loaded Metallic Loops Supporting Basic Voicegrade Services Approved April 2002 Prepared by T1E1.3 Working Group on Optical and Electrical Access T1.TRQ.7-2002 Foreword (This foreword is
6、 not part of T1.TRQ.7-2002.) This document is one of a series of standards and technical requirements documents developed by Technical Subcommittee T1E1 of Accredited Standards Committee T1, Telecommunications. Committee T1 serves the public through improved understanding between carriers, customers
7、, and manufacturers. In August, 2001, the Wireline Network Spectral Integrity Focus Group (FG3) of the Fifth Network Reliability and Interoperability Council (NRIC V) asked the Optical and Electrical Access Working Group (T1E1.3) to develop pass/fail performance criteria for non-loaded voicegrade me
8、tallic loops. NRIC was in the process of developing recommendations to the FCC concerning the sharing of information between service providers, loop providers, and equipment vendors regarding spectral compatibility. One of their fundamental assumptions was that xDSL services could typically be deplo
9、yed on non-loaded metallic loops that meet the minimum requirements for the support of basic voicegrade analog services like Plain Old Telephone Services (POTS). Prior to initiating the spectral interference dispute resolution process envisioned by NRIC, the service provider with the “victim“ servic
10、e has the responsibility of verifying that the associated non-loaded metallic loop meets the minimum requirements for the support of basic voicegrade analog services. With respect to these basic voicegrade analog pass/fail parameters, NRIC was unable to find a suitable industry standard, so they ask
11、ed the T1E1.3 Optical and Electrical Access Working Group to make recommendations. This technical requirements document was developed by T1E1.3 in response to that request. This Technical Requirement specifies end-to-end performance tests as well as single-ended performance tests. The document defin
12、es the methods, procedures, and equipment to be used for each test and it establishes the pass/fail criteria for each parameter being tested. Compliance with this technical requirements document should provide adequate support for basic voicegrade analog services, but this technical requirements doc
13、ument does not guarantee compatibility or acceptable performance for other types of services and technologies under all operating conditions. This technical requirements document will be useful to those engaged in the provisioning or operation of telecommunications equipment or services that utilize
14、 non-loaded metallic cables that have been designed and maintained to primarily support basic voicegrade analog services. Normative annexes are considered part of Committee T1 Technical Requirements. Informative annexes of Committee T1 Technical Requirements provide useful information but do not con
15、tain requirements. Similarly, footnotes are informative. This technical requirements document was developed by T1E1 in accordance with ANSI and Committee T1 procedural guidelines and represents the consensus position of the formulating group. This document was processed and approved for submittal to
16、 ATIS by the Accredited Standards Committee on Telecommunications, T1. Committee approval of this technical requirements document does not necessarily imply that all committee members voted for its approval. Future control of this technical requirements document will reside with Alliance for Telecom
17、munications Industry Solutions (ATIS). Suggestions for improvement of this document are welcome. These should be sent to the Alliance for Telecommunications Industry Solutions, T1 Secretariat, 1200 G Street, NW, Suite 500, Washington DC 20005. These requirements were developed in Technical Subcommit
18、tee T1E1 Interfaces, Power, and Protection of Networks. E. Eckert, T1E1 Chair R. Townsend, T1E1 Vice Chair N. Butler, T1E1 Secretary C. Underkoffler, T1 Chief Editor iiT1.TRQ.7-2002 Working Group T1E1.3 Optical and Electrical Access developed this technical requirements document. During the developm
19、ent of this document, the following individuals participated in the Working Group: T. Bishop, T1E1.3 Chair and Editor M. Wright, T1E1.3 Vice Chair L. Allred E. Eckert B. Ogren R. Bobilin F. Fainaru C. Posthuma C. Brownmiller P. Galarza D. Reed B. Buckley R. Gonzales R. Rice W. Cardenette R. Goodson
20、J. Salinas G. Cerull S. Iwasaki P. Taffinder C. Chamney D. Mathews G. Tennyson M. Cook T. Miller R. Townsend P. Dillon J. Morgan S. Whitesell P. Donaldson G. Neumeier A. Wilson iii T1.TRQ.7-2002 Table of Contents 1 SCOPE 1 2 NORMATIVE REFERENCES . 1 3 DEFINITIONS 1 4 ABBREVIATIONS, ACRONYMS, AND SYM
21、BOLS 2 5 TECHNICAL CRITERIA 3 5.1 END-TO-END TEST PARAMETERS 3 5.1.1 LOOP CURRENT/LOOP RESISTANCE. 3 5.1.1.1 LOOP CURRENT . 3 5.1.1.2 LOOP RESISTANCE . 3 5.1.2 C-MESSAGE METALLIC NOISE . 4 5.1.3 1004 HZ TRANSDUCER LOSS 4 5.1.4 OTHER END-TO-END TEST PARAMETERS . 5 5.1.4.1 ATTENUATION DISTORTION 5 5.1
22、.4.2 RETURN LOSS, IMPULSE NOISE, AND ENVELOPE DELAY DISTORTION 5 5.2 SINGLE-ENDED TEST PARAMETERS . 5 5.2.1 INSULATION RESISTANCE 6 5.2.2 FOREIGN DC VOLTAGE 6 5.2.3 FOREIGN AC VOLTAGE 7 5.2.4 CAPACITIVE BALANCE . 8 A BIBLIOGRAPHY. 10 Table of Tables Table 1 - Summary of Technical Requirements for No
23、n-Loaded Metallic Loops Supporting Basic Voicegrade Services. 9 ivT1.TRQ.7-2002 Technical Requirements for Non-Loaded Metallic Loops Supporting Basic Voicegrade Services 1 Scope This document provides a minimal set of pass/fail performance parameters for non-loaded metallic loops that have been desi
24、gned and maintained to primarily support basic voicegrade analog services such as Plain Old Telephone Services (POTS). The document specifies end-to-end performance tests as well as single-ended performance tests. The document defines the methods, procedures, and equipment to be used for each test,
25、and establishes the pass/fail criteria for each parameter being tested. Compliance with this technical requirements document should provide compatibility for basic voicegrade analog services in most cases, but this document does not guarantee compatibility or acceptable performance for all services
26、and technologies under all operating conditions. Tariffs, contracts, or regulatory acts in various jurisdictions may contain additional or more stringent requirements than those specified in this technical requirements document. In accordance with ANSI guidelines, two categories of specifications ar
27、e used in this document, mandatory requirements and recommendations. Mandatory requirements are designated by the word “shall“ and recommendations by the word “should.“ 2 Normative References The following standard contains provisions that, through reference in this text, constitute provisions of th
28、is technical requirements document. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this document are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below.
29、Informative references are provided in Annex A. 743-1995, IEEE Standard Equipment Requirements and Measurement Techniques for Analog Transmission Parameters for Telecommunications.13 Definitions 3.1 customer installation (CI) All telecommunication equipment and wiring on the customer side of the net
30、work demarcation point. 1This document is available from the Institute of Electrical and Electronics Engineers (IEEE). 1 T1.TRQ.7-2002 3.2 network interface (NI) demarcation point: The point of connection between network facilities and the Cl. 3.3 splitter A network comprised of frequency-domain fil
31、ters that separate high-frequency xDSL (e.g., ADSL) signals from voicegrade signals to facilitate the deployment of xDSL and voicegrade services over the same non-loaded metallic facility. 3.4 terminal equipment Communications equipment located on customer premises at the end of a communications lin
32、k that is used to permit the stations involved to accomplish the provision of telecommunications or information services. 3.5 voicegrade - A term used to qualify a channel, facility, or service that is suitable for the transmission of speech, data, or facsimile signals; generally with a frequency ra
33、nge of about 300 to 3000 Hz. The term is also used to describe a signal with a frequency range of about 300 to 3000 Hz. 4 Abbreviations, Acronyms, and Symbols ac alternating current ADSL Asymmetrical Digital Subscriber Line ANSI American National Standards Institute ATIS Alliance for Telecommunicati
34、ons Industry Solutions CI Customer Installation CO Central Office dB decibel (i.e., one tenth of a bel) dBm decibels referenced to one milliwatt dBrnC decibels referenced to noise with C-message weighting dc direct current DDS Digital Data Service DSL Digital Subscriber Line FCC Federal Communicatio
35、ns Commission FG3 Wireline Network Spectral Integrity Focus Group Hz hertz IEEE Institute of Electrical and Electronics Engineers, Inc. mA Milliamperes NI Network Interface NRIC V Fifth Network Reliability and Interoperability Council POTS Plain Old (analog) Telephone Service REG Range Extender with
36、 Gain T1 Committee T1V volts xDSL any Digital Subscriber Line technology 2 T1.TRQ.7-2002 5 Technical Criteria A fundamental assumption in the telecommunications industry is that basic voice services and xDSL services can be deployed on non-loaded metallic loops that meet the minimum requirements for
37、 the support of basic voicegrade analog services like POTS. This document defines the applicable end-to-end and single-ended performance tests for the support of basic voicegrade analog services. It also defines the methods, procedures, and measurement equipment to be used for each test and the pass
38、/fail criteria for each parameter being tested. A summary of the pass/fail criteria for each parameter is provided in Table 1. 5.1 End-to-End Test Parameters Most POTS installer/repairman in the United States carry a test set that allows them to measure loop current, 1004 Hz transducer loss, and C-m
39、essage metallic noise. If a metallic loop passes those three tests, then it is considered qualified for basic voice services like POTS, and further tests are not ordinarily necessary. 5.1.1 Loop Current/Loop Resistance. To measure loop current, a battery feed needs to be connected to the loop. On sh
40、ared loops (i.e., a loop that is used simultaneously for a voice service and an above-the-voiceband data service), the Central Office (CO) switching system (or other network element) provides a battery feed that will facilitate loop current testing. If a loop used for xDSL is not shared with a voice
41、 service, then a battery feed may not be present to facilitate loop current testing. In cases where a battery feed is present for sealing current or line powering purposes, in all likelihood it will not meet the voltage versus current characteristics for loop-start and ground-start access lines in T
42、1.401-2000. For these reasons, if a non-loaded metallic loop used for xDSL does not share the loop with a loop-start or ground-start service, then a dc loop current measurement may not be feasible. In such cases, a loop resistance test should be made instead of the loop current test. 5.1.1.1 Loop Cu
43、rrent Loop current on loop-start and ground-start lines shall be measured with a 430-ohm load substituted for the Customer Installation (CI) at the Network Interface (NI). In accordance with T1.401-2000, the minimum loop current requirement under normal commercial power conditions shall be 20 mA. (T
44、his is equivalent to 8.6 V dc across a 430-ohm load at the NI.) 5.1.1.2 Loop Resistance Loop resistance is measured with an ohmmeter connected between the tip and ring conductors at one end of the loop with the conductors at the far end of the loop shorted. To obtain an accurate reading, customer pr
45、emises wiring and series equipment (e.g., CO or CI splitters) should not be included when making loop resistance measurements. The maximum expected loop resistance varies depending upon the original design of the loop. If the loop was originally designed using non-loaded resistance design criteria,
46、then the loop resistance should not exceed 1300 ohms. 3 T1.TRQ.7-2002 If a loop was originally designed using some other type of loop design guidelines, then the loop resistance could be greater than 1300 ohms. For example, if the metallic loop was designed according to loaded resistance design crit
47、eria and the load coils were then subsequently removed to facilitate xDSL service, then the loop resistance could be as much as 1500 ohms. Likewise, if load coils were not placed on long loops to facilitate other types of digital services, then the resistance could be as much as 1500 ohms or even mo
48、re. In the extreme case, if a metallic loop was designed according to loaded Long Route Design criteria with a Range Extender with Gain (REG) and the load coils and REG were subsequently removed, the resistance could be as much as 3600 ohms. 5.1.2 C-Message Metallic Noise For voicegrade services, me
49、tallic (i.e., tip-to-ring) noise is a primary performance parameter since it is the metallic (differential mode) noise not the longitudinal (common mode) noise that people hear. Noise-to-ground measurements and noise balance calculations are considered to be diagnostic in nature and thus are pertinent only when a loop fails the metallic noise limit. The industry standard for voiceband metallic noise test procedures is IEEE 743. That standard defines the C-Message weighting filter, appropriate terminations, and testing methodology. C-Message metallic noise is measured at the NI wit
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