1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU E.18OIQ.35 (03/98) SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS Operation, numbering, routing and mobile services - International operation - Tones in national s
2、ignalling systems SERIES Q: SWITCHING AND SIGNALLING International automatic and semi-automatic working - Tones for use in national signalling systems Technical characteristics of tones for the telephone service ITU-T Recommendation E.180/Q.35 (Previously CCITT Recommendation) ITU-T E-SERIES RECOMME
3、NDATIONS OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HMAN FACTORS OPERA TION, NUMBERING, ROUTING AND MOBILE SER VICES INTERNATIONAL OPERATION Definitions General provisions concerning Administrations General provisions concerning users Operation of international telephone ser
4、vices Numbering plan of the international telephone service International routing plan E. 100-E. 103 E. 104-E. 1 19 E. 120-E. 139 E.140-E.159 E. 160-E. 169 E.170-E.179 _. Iones in national signalling systems 1.:.180-E.100 Maritime mobile service and public land mobile service E.200-E.229 OPERATIONAL
5、 PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON- TELEPHONY APPLICATIONS ISDN PROVISIONS CONCERNING USERS E.330-E.399 QUALITY OF SER VICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING NETWORK MANAGEMENT TR
6、AFFIC ENGINEERING QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING For further details, please refer to ITU-T List of Recommendations. ITU-T Q- SERIE S RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE INTERNATIONAL
7、AUTOMATIC AND SEMI- AUTOMATIC WORKING Q.14.3 Q.44.5 9 Basic Recommendations Q.44.9 Numbering plan and dialling procedures in the international service Routing plan for international service General Recommendations relative to signalling and switching systems (national or international Q.lO4.11 Q. 12
8、4.19 Q.204.34 Tones for use in national signalling systems 0.35-0.3) General characteristics for international telephone connections and circuits Signalling for satellite systems Signalling for circuit multiplication equipment FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN CLAUSES APPLICAB
9、LE TO ITU-T STANDARD SYSTEMS SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 SPECIFICATIONS OF SIGNALLING SYSTEM R1 SPECIFICATIONS OF SIGNALLING SYSTEM R2 DIGITAL EXCHANGES INTERWORKING OF SIGNALLING SYSTEMS SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 DIG
10、ITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 PUBLIC LAND MOBILE NETWORK INTERWORKING WITH SATELLITE MOBILE SYSTEMS INTELLIGENT NETWORK BROADBAND ISDN Q.404.47 Q.484.49 Q.504.59 Q.604.99 Q.lOO4.119 Q. 1204.249 Q.2504.309 Q.3104.399 Q.4004.499 Q.5004.599 Q.6004.699 Q.7004.849 Q.8504.999 Q. 1 0004. 1099 Q.1
11、100.1199 Q. 12004.1999 Q.20004.2999 For further details, please refer to ITU-T List of Recommendations. ITU-T RECOMMENDATION E.180/Q.35 TECHNICAL CHARACTERISTICS OF TONES FOR THE TELEPHONE SERVICE Summary This Recommendation sets the limits and recommended values of cadences, frequencies and levels
12、for tones used in the telephone service. Those technical characteristics are relevant either for audible tones applied within the network or for those generated at the digital terminal equipment. Source ITU-T Recommendation E.180/Q.35 was revised by ITU-T Study Group 2 (1997-2000) and was approved u
13、nder the WTSC Resolution No. 1 procedure on the 9th of March 1998. Recommendation E.180/Q.35 (03/98) i FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommuni- cations. The ITU Telecommunication Standardization Sector (ITU-T) is a per
14、manent 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 standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four yea
15、rs, 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 the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall
16、 within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, the expression “Admmistration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIG
17、HTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether assert
18、ed 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 of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautione
19、d 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 of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microf
20、ilm, without permission in writing from the ITU. 11 Recommendation E.180/Q.35 (03/98) CONTENTS 1 2 3 4 5 6 7 8 9 10 11 12 General . Electrical levels for tones . Acoustical levels for tones Dial tone . Ringing tone . Busy tone and congestion tone . Special information tone . Warning tone to indicate
21、 that a conversation is being recorded . Payphone recognition tone . 9.3 Duration and level . Call waiting tone . Caller waiting tone Machine recognition of tones . Annex A Digital generation of tones Annex B Examples for limitation of spurious components of the dial tone with respect to interferenc
22、e with the frequencies recommended for pushbutton telephone sets in Recommendation Q.23 B . 1 Method A (used by ATT) B.2 Method B (used by the Federal Republic of Germany) Recommendation E.180/Q.35 (03/98) Page 1 1 2 3 3 4 6 6 6 7 7 7 8 8 9 9 9 . 111 Recommendation E.180/Q.35 TECHNICAL CHARACTERISTI
23、CS OF TONES1 FOR THE TELEPHONE SERVICE (revised in 1998) 1 General Administrations are reminded of the advantages of standardizing audible tones as far as possible so that subscribers and operators may quickly recognize any tone transmitted of whatever origin2. Guidance on the application of tones a
24、nd recorded announcements in various situations is given in Recommen- dation E. 182. In considering the degree of standardization, the ITU-T took account of the nature of the various tones already in use. It was also considered that Admmistrations introducing new tones would fiid it helpful to know
25、the preferred limits of cadence, frequency and level. Limits for tone cadences and frequencies are set forth below, all working tolerances being included in the limits. Besides the limits applying to specifications, limits have been laid down for application to existing exchanges. These latter limit
26、s are herein called accepted limits, while those for new equipment are called recommended limits. The present Recommendation covers the case where audible tones are applied within the network. However, the same frequencies and cadences are to be applied if, in the ISDN, the audible tones are generat
27、ed at the terminal equipment. All Administrations and operating agencies are requested to submit a concise technical description of any new or changed network tones to the ITU-T whenever such tones are introduced. The technical detail should include: level, frequencies, cadence, duty cycle, modulati
28、on and any other parameters that are required to fully describe the new or changed network tone. 2 Electrical levels for tones For international purposes, the levels of the ringing tonethe busy tone, the congestion tonethe special information tone and the warning tonehave to be defined at a zero rel
29、ative level point at the incoming (in the traffic direction) end of the international circuit. The level of tones so defiied must have a nominal value of -10 dBmO. The recommended limits should be not more than -5 dBmO nor less than -1 5 dBmO measured with continuous tone. For the special informatio
30、n tone, a difference in level of 3 dB is tolerable between any two of the three frequencies which make up the tone. For the power level of the dial tone, the point of reference is the local exchange, where the subscriber line is connected. In the existing networks the absolute power at the 2-wire ac
31、cess in the direction towards the subscriber station is normally in the range of -10 dBm I 5 dB. However, with respect to interference with Multifrequency Pushbutton (MFPB) receivers dial tone levels higher than -1 O dBm should be avoided. See Supplement No. 2 at the end of the Blue Book, Fascicle 1
32、1.2, for particular values of tone cadences and frequencies in actual use. Recommendation E.181 specifies the information which could be given to users to facilitate recognition of foreign tones. Recommendation E.180/Q.35 (03/98) 1 NOTE - The relative level of local exchanges in an analogue network
33、is not fixed. For digital local exchanges the relative levels are given in Recommendation 4.517. A preferred level range of digital tone generators is -8 dBmO to -3 dBmO corresponding with the above level range at the output of local exchanges. 3 Acoustical levels for tones When tones are generated
34、by a source within a network, e.g. by a telephone exchange, the power level as perceived by the user will be influenced by the characteristics of the subscribers line and the equipment between the source and the users ear. Furthermore, tones can be generated within the users equipment, triggered by
35、signals from the exchange. In these circumstances it is necessary to define the tone level in terms of the preferred range of sound pressure levels as heard by the listener. Research has shown that the preferred listening level for information tones is substantially independent of room noise, circui
36、t noise and tone cadence, but does vary over a range of tone frequencies. Figure 1 shows the recommended sound pressure levels, with upper and lower limits of the recommended range, over a range of tone frequencies, based on these experiments. dBPa dBrap 10 8 6 4 $2 go i4 - In al TI a -2 4 -8 -1 o U
37、pperlimitofrecommended 1 1 1 1 1 104 102 1 O0 98 96 In 94 y c al al - 92 90 88 86 84 -1 2 T0207440-98/dO 1 Frequency Figure UE.180 - Recommended listening level limits for tones It is emphasized that there is no one-to-one relationship between electrical and acoustical power levels. What acoustic le
38、vel will result from a given electrical level is dependent on various parameters such as the characteristics of the users equipment. It should be noted that the recommended sound pressure levels apply only to the most common situation of a user listening via a telephone handset, held reasonably clos
39、e to the ear so that normal “ear coupling loss“ values apply. When using a loudspeaking telephone or a headset, the preferred sound pressure level is generally lower than the recommended levels. 2 Recommendation E.180/Q.35 (03/98) 4 Dial tone 4.1 It is recommended that dial tone should be a continuo
40、us tone. 4.2 It is recommended that dial tone should be: - either a single frequency tone in the range 400-450 Hz; - or a combined tone composed of up to three frequencies, with at least one frequency in each of the ranges 340-425 Hz and 400-450 Hz. The difference between any two frequencies should
41、be at least 25 Hz. 4.3 Recognizing the local nature of “normal“ use of dial tone, as well as the technical and economic consequences and consequences on customer habits of changes in dial tone, the full range of existing dial tones, including non-continuous tones as in Supplement No. 2 at the end of
42、 Blue Book, Fascicle 11.2, are considered acceptable. However, when adopting a new single frequency dial tone, Administrations are recommended to use 425 Hz. 4.4 recommended for analogue generated tones (see Annex A). Where digital tone generation is applied, the frequencies for dial tone should be
43、the same as those 4.5 In order to prevent interference of harmonics or spurious components of the dial tone with the frequencies recommended for pushbutton telephone sets in Recommendation Q.23 and the MFPB signal reception specified in Recommendation Q.24, the maximum permissible power level of har
44、monics or quantizing noise of the dial tone has to be limited in a suitable way, depending on the specific characteristics of the implementations of the dial tone generator and the MFPB receivers within the same exchange. Examples of such limitations for the dial tone generator are given in Annex B.
45、 NOTE In cases of digital generation of the dial tone, the quantizing noise is composed of a number of spectral lines which depend on the number of samples in the generating pattern. In order to reduce the amplitude of the quantizing components, the number of samples should be chosen sufficiently hi
46、gh, thus spreading the quantizing distortion power more evenly over the whole spectrum. 5 Ringing tone 5.1 Ringing tone is a slow period tone, in which the tone period is shorter than the silent period. The recommended limits for the tone period (including tolerances) are from 0.67 to 1.5 seconds. F
47、or existing exchanges, the accepted upper limit for the tone period is 2.5 seconds. The recommended limits for the silent period separating two tone periods are 3 to 5 seconds. For existing exchanges, the accepted upper limit is 6 seconds. The first tone period should start as soon as possible after
48、 the called subscribers line has been found. Figure 2 shows the recommended and accepted limits for the ringing tone periods. 5.2 The ringing tone cadence should be similar to the cadence used for applying ringing current to the called subscribers telephone set, but these two cadences need not be sy
49、nchronized. The electrical parameters of the ringing current must be evaluated by the Administration concerned to prevent shock hazard. 5.3 The recommended frequency for the ringing tone is between 400 and 450 Hz. The accepted frequency should be not less than 340 Hz, nor more than 500 Hz. Frequencies between 450 and 500 Hz in the accepted frequency range should, however, be avoided. Admmistrations adopting a new single frequency ringing tone are recommended to use 425 Hz. The ringing tone frequency may be modulated by a frequency between 16 and 100 Hz, but such modulation is not
