1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STAN DARD IZAT ION SECTOR OF ITU G.51 I (02/98) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Testing equipments Test methodology for Group 3 facsimile processing equipment in the Public Switched Telephone Network
2、 ITU-T Recommendation G.511 (Previously CCIU Recommendation) ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100-G.199 INTERNATIONAL ANALOGUE CARRIER SYSTEM GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE C
3、ARRIER- Il TRANSMISSION SYSTEMS G.200-G.299 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE G.300-G.399 SYSTEMS ON METALLIC LINES GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION G.400-G.449 WITH METALLIC LINES COO
4、RDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450-G.499 11 TESTING EQUIPMENTS TRANSMISSION MEDIA CHA RA CTERIS TICS Gen era I Symmetric cable pairs Land coaxial cable pairs Submarine cables Optical fibre cables Characteristics of optical components and sub-systems DIGITAL TRANSMISSION SYSTEMS TER
5、MINAL EQUIPMENTS DIGITAL NETWORKS DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.600-G.609 G.610-G.619 G.620-G.629 G.630-G.649 G ,650-G . 659 G ,660-G . 699 G.700-G.799 G.800-G.899 G. 900-G. 999 For firther details, please refer to ITU-T List of Recommendations. ITU-T RECOMMENDATION G.511 TEST METHODOLO
6、GY FOR GROUP 3 FACSIMILE PROCESSING EQUIPMENT IN THE PUBLIC SWITCHED TELEPHONE NETWORK Summary This Recommendation defines the testing methodology for evaluating the performance of Group 3 facsimile processing equipment incorporated in Signal Processing Network Element (SPNE) of the Public Switched
7、Telephone Network. Source ITU-T Recommendation G.511 was prepared by ITU-T Study Group 16 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 6th of February 1998. STD-ITU-T RECMN G-511-ENGL 1778 48b257L Ob4b352 534 W FOREWORD ITU (International Telecommunication Union) is
8、the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to stand
9、ardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by
10、the Members of the IT-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, the expression “Administratio
11、n“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property
12、Right. The 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 Recommendation, the ITU had not received notice
13、 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. O ITU 1998 All rights reserved. No part
14、 of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. 11 Recommendation G.511 (02/98) 1 2 3 3.1 3.2 4 4.1 4.2 4.3 4.4 4.5 5 5.1 5.2 6 6.1 6.2 6.3 6.4 6.5 CONTENTS Sco
15、pe References Abbreviations and definitions . Abbreviations . Definitions Overview Addressed issues . Direction of transmission . Number of calls Test pages . Facsimile terminal selection . Facsimile terminal configurations Std/Conf/l : Reference configuration Standard Group 3 facsimile mode 5.1.1 5
16、.1.2 Std/Conf/2 . 5.1.3 Std/Conf/3 . 5.1.4 Std/Conf/4 . Non-standard Group 3 facsimile mode . 5.2.1 Non-standard Group 3 facsimile mode 1 5.2.2 Non-standard Group 3 facsimile mode 2 Network conditions Access-link impairments Access link impairments conditions Traffic loading 6.2.1 Definition 6.2.2 L
17、oading conditions Delay . Bearer impairments 6.1.1 Definition 6.1.2 6.4.1 Circuit-oriented CME 6.4.2 Identification of the bearer channels with markers . 6.4.3 Packet-oriented CME 6.4.4 Bearer conditions . Forward error correction . Recommendation G.511 (0298) Page 1 2 8 8 8 11 11 Il 12 12 12 13 14
18、15 15 16 . 111 6.6 Return echo level 6.7 Reference conditions Reference test condition 1 . Reference test condition 2 . Reference test condition 3 . Reference test condition 4 . Reference test condition 5 . Reference test condition 6 . Reference test condition 7 . Reference test condition 8 . 6.7.1
19、6.7.2 6.7.3 6.7.4 6.7.5 6.7.6 6.7.7 6.7.8 7 Facsimile call quality assessment . 8 Baseline measurements 8.1 Facsimile terminal baseline tests 8.2 CME baseline tests . 9 Test methodology . Annex A . Group 3 facsimile procedures . A . 1 Group 3 facsimile recognition: detection and classification A.l.l
20、 Objective . A.1.2 Settings A . 1.3 Test conditions A.1.4 Parameters of investigation . Monitoring/measurement points . A.2.1 Objective . A.2.2 Settings A.2.3 Test conditions A.2.4 Parameters of investigation . A.2.5 Monitoringmeasurement points . link impairments . A . 1.5 Proprietary facsimile fal
21、l-back to ADPCM path A.2 A.3 Group 3 facsimile image quality in presence of combined access link and bearer A.3.1 Objective . A.3.2 Settings A.3.3 Test conditions A.3.4 Monitoring/measurement points . Group 3 facsimile image quality in presence of bearer link impairments A.4.2 Settings A.4.4 Monitor
22、ing/measurement points . A.4 Page 16 16 16 16 17 17 17 17 18 18 18 19 19 21 21 24 24 24 24 24 24 24 24 24 25 25 25 25 25 25 25 26 26 26 26 26 iv Recommendation 6.511 (02/98) A . 5 A.6 A.7 A.8 A . 9 A.10 CME recovery following unexpected events during facsimile call progress . A.5.1 Objective . A.5.2
23、 Settings A.5.3 Test conditions Voiceband data quality . A.6.1 Objective . A.6.2 Settings A.6.3 Test conditions A.6.4 Monitoring/measurement points . Effect of Group 3 facsimile protocol variability A.7.1 Objective . A.7.2 Settings A.7.3 Test conditions A.7.4 Parameters of investigation . Effect of
24、transmission level and echo return loss . A.8.1 Objective . A.8.2 Settings A.8.3 Test conditions A.8.4 Parameters of investigation . A.8.5 Monitoring/measurement points . Impact of transmission integrity due to timing deviations on facsimile call quality A.9.1 Objective . A.9.2 Settings A.9.4 Monito
25、ring/measurement points . Items for further study A . 1 O . 1 Rates and modulation schemes . A . 10.2 Facsimile quality assessment A . 10.3 Coding algorithms . A.9.3 Test conditions A.10.4 Errors . A . 10.5 CME networks . A . 10.6 Other SPNE . Appendix I . Identifying a demodulated call in a DCME .
26、I . 1 Principles 1.2 Implementation . Recommendation G.511 (02198) Page 26 26 26 27 28 28 28 28 28 29 29 29 29 29 30 30 30 30 30 30 31 31 31 31 31 31 31 31 31 32 32 32 32 32 33 V Recommendation 6.511 Calling TEST METHODOLOGY FOR GROUP 3 FACSIMILE PROCESSING EQUIPMENT IN THE PUBLIC SWITCHED TELEPHONE
27、 NETWORK (Geneva, 1998) Called 1 Scope This Recommendation defines the testing methodology for evaluating the performance of Group 3 facsimile processing equipment incorporated in Signal Processing Network Element (SPNE) of the Public Switched Telephone Network. The testing methodology covers the fo
28、llowing aspects: 1) 2) 3) facsimile recognition (i.e. detection and classification); proprietary facsimile fall-back to ADPCM path; Group 3 facsimile image quality in presence of: a) combined access link impairments and bearer link impairments; b) bearer link impairments; recovery following unexpect
29、ed events during the facsimile call Set-up; effect of variability in the implementation of the T.30 protocol; effects of transmission level variation and echo return loss; impact of transmission integrity due to timing deviations on facsimile call quality. 4) 5) voiceband data quality; 6) 7) f-9 The
30、 basic configuration employed in these tests is shown in Figure 1. v, FAX Calling end - Access-link impairments SPNE SPNE other traffic 7 - Bearer-link impairments a Access-link impairments Called end I Other traffic direction of document transmission c T1600540-97 Figure UG.511- Basic configuration
31、 for testing facsimile processing equipment in Signal Processing Network Element (SPNE) Recommendation G.511 (02/98) 1 In Figure 1, SPNE represents a signal processing network element. In general, this SPNE can process other signals than facsimile signals. However, only the Group 3 facsimile process
32、ing aspects of Circuit Multiplication Equipment (CME) and Echo Cancellers (EC) is discussed in this Recommendation. Other types of SPNE are for further study. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute pr
33、ovisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recomm
34、endations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. ITU-T Recommendation E.45 1 (1 993), Facsimile call cut-offperformance. ITU-T Recommendation E.452 (1 993), Facsimile modem speed reductions and transaction time. ITU-T Recommenda
35、tion E.453 (1 994), Facsimile image quality as corrupted by transmission-induced scan line errors. ITU-T Recommendation E.456 (1 994), Test transaction for facsimile transmission performance. ITU-T Recommendation G.701 (1 993), Vocabulary of digital transmission and multiplexing, and Pulse Code Modu
36、lation (PCM) terms. CCITT Recommendation G.7 1 1 (1 9984, Pulse Code Modulation (CPM) of Voice- Frequencies. ITU-T Recommendation G. 165 (1 993), Echo cancellers. ITU-T Recommendation G.720 (1 995), Characterization of low-rate digital voice coder performance with non-voice signals. CCITT Recommenda
37、tion G.726 (1990), 40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code Modulation (ADPCM). CCITT Recommendation G.727 (1990), 5, 4, 3- and 2-bits/sample embedded Adaptive Diflerential Pulse Code Modulation (ADPCM). CCITT Recommendation G.728 (1992), Coding of speech at 16 kbit/s using low-deZay c
38、ode excited linear prediction. ITU-T Recommendation G.729 (1996), Coding of speech at 8 kbit/s using conjugate structure Algebraic-Code-Excited Linear Prediction (CS-ACELP). CCITT Recommendation G.763 (1 99 i), Digital circuit multiplication equipment using ADPCM Recommendation G. 726 and digital sp
39、eech interpolation. CCITT Recommendation G.764 (1 990), Voice packetization - Packetized voice protocols. CCITT Recommendation G.765 (1 992), Packet circuit multiplication equipment. CCITT Recommendation G.766 (1 992), Facsimile demodulatiodremodulation for DCME. ITU-T Recommendation G.826 (1 993),
40、Error performance parameters and objectives for international, constant bit rate digital paths at or above the primary rate. ITU-T Recommendation T.4 (1 996), Standardization of Group 3 facsimile apparatus for document transmission. 2 Recommendation G.511 (02/98) ITU-T Recommendation T.22 (1 993), S
41、tandardized test charts for document facsimile transmission. ITU-T Recommendation T.30 (1 996), Procedures for document facsimile transmission in the general switched telephone network. CCITT Recommendation V. 17 (1 99 i), 2-Wire modem for facsimile applications with rates up to 14 400 bith. CCITT R
42、ecommendation V.21 (1984), 300 bits per second duplex modem standardized for use in the general switched telephone network. CCITT Recommendation V.27 ter (1 984), 4800/2400 bits per second modem standardized for use in the general switched telephone network. CCITT Recommendation V.29 (1 988), 9600 b
43、its per second modern standardized for use on point-to-point 4-wire leased telephone-type circuits. CCITT Recommendation V.33 (1 SSS), 14 400 bits per second modem standardized for use on point-to-point 4-wire leased telephone-type circuits. ITU-T Recommendation V.34 (1996), A modem operating at dat
44、a signalling rates of up to 33 600 bith for use on the general switched telephone network and on leasedpoint-to-point 2-wire telephone type circuits. Abbreviations and definitions Abbreviations This Recommendation uses the following abbreviations: CME Circuit Multiplexing Equipment DCME EC HOL OL OL
45、F PCME SPNE UL Digital Circuit Multiplexing Equipment (see Recommendation G.763) Echo Canceller (see Recommendation G. 165) Heavy overload condition with speech traffic in a CME Overload condition with speech traffic in a CME Overload condition due to facsimile in a CME Packet Circuit Multiplexing E
46、quipment (see Recommendation G.765) Signal Processing Network Element. Examples: DCME, PCME, EC Underload condition with speech traffic in a CME 3.2 Definitions This Recommendation defines the following terms: 3.2.1 ADPCM path: This is the transmission path within the CME when the facsimile signal i
47、s going through the ADPCM encodeddecoder. 3.2.2 control channel: In a circuit-oriented circuit multiplication equipment, the control channel is a unidirectional transmission path from the transmit unit of one CME to the receive unit of one or more associated CMEs. This control channel is dedicated p
48、rimarily to carrying channel assignment messages. In addition, the control channel transmits other messages such as idle noise level, dynamic load control, alarm messages and optionally, line signalling information. Recommendation G.511 (0298) 3 For a packet-oriented circuit multiplication equipment
49、, the CME control channel is either the packet header of a packet carrying the users traffic or a special packet carrying control information. 3.2.3 demodulated transmission path: This is the path of the facsimile signal when the baseband signal has been extracted by demodulation. 3.2.4 facsimile demodulation/remodulation: This is the processing function in a CME where facsimile is discriminated from voiceband data and subsequently demodulated to recover the baseband digital signal. It is then remodulated at the terminating CME. 3.2.5 forward bearer channel: This is the bearer c
