1、CCITT RECMN+M=4030 92 4862593 0579Lb7 730 W INTERNATIONAL TELECOMMUNICATION UNION CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITTEE MAINTENANCE: COMMON CHANNEL SIGNALLING SYSTEMS M.4030 (1 0/92) TRANSMISSION CHARACTERISTICS FOR SETTING UP AND LINING UP A TRANSFER LINK FOR COMMON
2、 CHANNEL SIGNALLING SYSTEM No. 6 (ANALOGUE VERSION) Recommendation M.4030 CCITT RECMN*M.4030 92 486253L C1579Lb8 657 FOREWORD The CC (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU). CCITT is responsible for st
3、udying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The Plenary Assembly of CCIT which meets every four years, establishes the topics for study and approves Recommendations prepared by its Study Gr
4、oups. The approval of Recommendations by the members of CCI?IT between Plenary Assemblies is covered by the procedure laid down in CC Resolution No. 2 (Melbourne, 1988). Recommendation M.4030 was revised by Study Group IV and was approved under the Resolution No. 2 procedure on the 5th of October 19
5、92. CCI?IT NOTE I In this Recommendation, the expression ?Administration? is used for conciseness to indicate both a telecommunication administration and a recognized private operating agency. O ITU 1993 All rights reserved No part of this publication may be reproduced or utilized in any form or by
6、any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. CCITT RECMN*M-4030 92 48b257L 0579Lb9 593 Recommendation M.4030 TRANSMISSION CHARACTERISTICS FOR SETTING UP AND LINING UP A TRANSFER LINK FOR COMMON CHANNEL SIGNALLING SYSTEM No. 6
7、(ANALOGUE VERSION)1) (Published 1980 as M.761; revised and renumbered in 1992) Abstract Provide details of the transmission characteristics required of a link which will be used for the exchange of signaiiing information in the common channel Signalling System No. 6 format. Keywords - liningup; - Si
8、gnalling System No. 6; - transfer link, - transmission characte 1 Setting up and iining up a transfer link 1.1 The method to be used and procedure to be followed in setting up and lining up a transfer link are similar to those given in Recommendation M.1050 i in so far as it applies. However, in thi
9、s context, any reference to national sections in Recommendation M.1050 i should be ignored since a transfer link exists between terminal international centres and does not include nAtional sections. 1.2 Routing restrictions may be necessary to achieve the loss/fiequency and group-delay distortion li
10、mits specified below if the need to insert equalizers is to be avoided. Factors that may contribute to difficulties in meethg these limits are the number of through-group filters in group links, the use of edge band channels in group links, etc. In addition, the number of channel translating equipme
11、nt should be minimized in order that equalization, if required, may be more easily achieved, and that the effect of other parameters, such as noise, may be minimized. 2 Transmission characteristics of a transfer link 2.1 General The transmission characteristics of the circuit to be used as the signa
12、lling data link are based on those for international leased circuits conforming to Recommendation M. 1020 2. ptionaily, the relaxed overall loss/frequency characteristic and group-delay distortion limits specified in Recommendation Q.272 3 may be applied where agreed between the Administrations invo
13、lved and if tests confm suitability. 2.2 Overall loss at reference frequency The overail loss at reference frequency of the channels of a transfer link is not specified. A general description of the transfer link for the common channel Signalling System No. 6 may be found in Recommen- dation M.760 6
14、1. Recommendation M.4030 (10i92) 1 The channels of a transfer link should be set up so that when a test signai at a level of -10 dBmO is connected to the input of the iransfer channel, the level received at the output of the transfer channel at the distant end is as close as possible to -10 dBm0. 2.
15、3 variation with time of the overall loss at reference frequency The variation with time of the overall loss at reference frequency should be as smaU as possible but should - - not exceed the following limits: short-term variation (over a period of a few seconds): f 3 dB; long-term vanation (over lo
16、ng periods including daily and seasonal variations): f 4 dB. 2.4 Losdfiequency distortion2) lits shown in Figure 1M.4030. The variation of overali loss with frequency relative to the loss at reference frequency should not ex& the O -1 -2 o 300500 28003000 Hz Frequency TOu)4210-93/dOl Note i - Below
17、300 Hz and above 3000 Hz the loss shall not be less than 0.0 dB but is otherwise unspecified. Note 2 - 1020 Hz is the reference test frequency as explained in Recommendation 0.6 7. FIGURE 1FI.4030 Limits for overall loss of the transfer link relative to that at reference frequency 2, The lits of Rec
18、ommendation M.1020 2 have been chosen for the losdfrequency characteristics although these limits are appropriate for a leased circuit extending over national plant including local lines to customers premises. Transfer links will only extend between international centres and their routing will not i
19、nvolve any audio line plant with its inherent increasing attenuation with equency. 2 Recommendation M.4030 (10192) CCITT RECMN*M*4030 92 R 4862593 0579171 141 2.5 Group-delay distortion The group-delay distortion relative to the minimum delay should not exceed the limits shown in Figure 2M.4030. O 5
20、00600 1000 2Ooo 26002800 Hr Frequency TC4422093/dZ FIGURE 2m.4030 Limits for group delay relative to the minimum measured group delay in the 500-2800 Hz band Note - It is believed that in many cases the limits specified in $0 2.4 and 2.5 may be achieved without the addition of equalizing equipment.
21、2.6 Random noise The level of the psophometric noise power at the receiving terminal international centre depends upon the actuai length and constitution of the transfer link. The provisional limit for transfer links of distances greater than 10 O00 km is -38 dBmOp. However, transfer links of shorte
22、r length will have substantially less random noise, as shown in Figure 3M.4030. Figure 3M.4030 displays random noise versus length and is presented as a guide to the random noise performance which may be found on a transfer link. Note - For transfer links routed via satellite, the satellite section
23、(between earth stations) will contribute approximately 10 O00 pWOp (-50 dBm0p) to the overall circuit noise. Therefore, for the purpose of determining the noise limits for the Signalling System No. 6 transfer link, the section of the transfer link provided by the satellite may be considered to be eq
24、uivalent to a length of loo0 km. The effective noise length of such a transfer link will be loo0 km plus the total length of the terminal routings. 2.7 Impulsive noise Impulsive noise should be measured with an insirument complying with RecommendationO.71 4. As a provisional hit, the number of impul
25、sive noise peaks exceeding -21 dBm0 should not be more than 18 in 15 minutes. Recommendation M.4030 (10192) 3 CCITT RECMN*M*4030 92 W 486259% 0579372 088 W dBm0p 500 IO00 2Ooo Circuit length 5000 IOOOO 20000krn T0404230-93d03 FIGURE 3N.4030 Random noise performance 2.8 Phase jitter The value of phas
26、e jitter depends upon the actual constitution of the transfer link (for example, upon the number of modulation equipment involved). It is expected that any measurement of phase jitter using an instrument complying with Recommendation 0.91 5 will not normally exceed 10“ peak-to-peak. However, for tra
27、nsfer links of necessarily complex constitution, and where 10“ peak-to-peak cannot be met, a limit of up to 15“ peak-to-peak is permitted. 2.9 Quantizing noise If any section of the transfer link is routed over a pulse code modulation system or through a digital exchange, the signal will be accompan
28、ied by quantizing noise. The minimum ratio of signal-to-quantizing noise normally expected is 22 dB. 2.10 Single tone interference The level of single tone interference in the band 300-3400 Hi shall not exceed a value which is 3 dB below the circuit noise objective indicated in Figure 3M.4030. 2.11
29、Frequency error The frequency error introduced by the transfer link must not exceed f 5 Hz. It is expected that in actual practice the frequency errors encountered will be less than 5 Hz. 2.12 Harmonic distonion When a 700-Hz test frequency at -13 dBmO is injected at the transmit end of the transfer
30、 link, the level of any individual harmonic frequency at the receiving end shall be at least 25 dB below the received level of the fundamental frequency. 4 Recommendation M.4030 (10/92) CCITT RECMNxM.qo30 92 4862591 0579373 TI4 = 3 Recording of results Ail measurements made in completing the line-up
31、 of the transfer link are valuable as references. These final measurements should be recorded using an appropriate form. If subsequent realignment or adjustment is necessary, these records should be updated. References il CCIT Recommendation M. 1050 Lining up an international point-to-point leased c
32、ircuit. 21 CCITT Recommendation M. 1020 Characteristics of special quality international leased circuits with special bandwidth conditioning. 31 CCITT Recommendation Q.272 Requirements for the signalling data link, Annex. 41 CCITT Recommendation 0.71 Impulsive noise measuring equipment for telephone
33、-type circuits. 151 FI 71 CCIT Recommendation 0.9 1 Phase jitter measuring equipment for telephone circuits. CCIT Recommendation M.760 Transfer link for common channel Signalling System No. 6. CCITT Recommendation 0.6 1020 Hz Reference testfrequency. Recommendation M.4030 (10/92) 5 CCITT RECMN+M*4030 92 I 4862591 0579174 750 I Printed in Switzerland Geneva, 1993
