1、CCITT RECMN+O-33 92 4862593 0579370 UT3 INTERNATIONAL TELECOMMUNICATION UNION CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITTEE 0.1 1 (1 0/92) SPECIFICATIONS OF MEASURING EQUIPMENT I MAINTENANCE ACCESS LINES Recommendation 0.1 1 CCITT RECMN*O=LL 92 4Lb259L 0579LqL T3T FOREWORD T
2、he CCIT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU). CCIT is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunic
3、ations 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 Groups. The approval of Recommendations by the members of CCITT between Plenary Assemblies is covered by the procedure laid down
4、 in CCIT Resolution No. 2 (Melbourne, 1988). Recommendation 0.11 was revised by Study Group IV and was approved under the Resolution No. 2 procedure on the 5th of October 1992. CC NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunicatio
5、n administration and a recognized private operating agency. O ITU 1993 Ail 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 mcrofii, without permission in writing from the ITU. CCITT RECMN*O.1
6、1 92 D Y862591 0579192 976 = Recommendation 0.11 MAINTENANCE ACCESS LINES (Published 1972; revised 1984, 1988, and 1932) Abstract Defines a number of test access lines for manual and automatic maintenance of international circuits. Keywords - automatic testing; - maintenance access lines; - testing.
7、 1 General 1.1 Introduction In order to carry out manual and automatic maintenance of international circuits in an automatic telephone network more effectively, the following international maintenance access lines are recommended: a) a balanced quiet termination which initially returns a -10 dBmO te
8、st tone; b) a maintenance test position or console access line with multiple access codes for both voice communications andor circuit testing; c) a test line to terminate the echo suppressor testing system (ESTS); d) a loopback test line (analogue or digital); e) a test line to terminate the echo ca
9、nceller test responder; f) a test line to terminate the signalling system functional testing and transmission measuring responder (type a) for use with ATME No. 2 (see Recommendation 0.22 6); g) a test line which returns a busy flash signal for use with ATME No. 2 (also referred to as type c respond
10、ing equipment, see Recommendation 0.22 6). These test lines should be provided as modular units so that each Administration may choose the number of each type it wishes to install at a given centre. The test lines listed in a) to e) above will not provide reliable test results for a circuit which is
11、 routed through a circuit multiplication system (CMS) employing interpolation techniques this includes the case where a circuit is routed over time division multiple access/digital speech interpolation (TDMA/DSI) satellite channels and therefore should not be used in this instance unless a permanent
12、 trunk-channel association in both directions of transmission can be mae for the duration of the test sequence. The reason for this is that without such a trunk-channel association, circuit continuity may not be maintained within the CMS in the absence of a signal and during very low signal level co
13、nditions. Recommendation 0.11 (10/92) 1 CCITT RECNN*O-LL 92 I 4Bb259L 0579193 802 1.2 Quiet termination test line The quiet termination test line is a dialable test line that initially returns a nominal 1020 Hz) -10 dBm0 tone for 13 to 15 seconds. After the initial tone period, the test line should
14、present a balanced 6-ohm termination to simulate the nominal exchange impedance. This quiet termination should remain connected until the cdling party disconnects. This dialable test line is intended to allow one-man manual 1-way loss, 1-way noise (or noise with tone) measurements and impulsive nois
15、e checks on any circuit from the distant switching centre. 1.3 Test ador communications access line The test and/or communications access line is a dialable access line intended to be located at the circuit maintenance test position or test console location associated with the international switchin
16、g centres. These access lines are expected to be used for voice communications between the circuit maintenance personnel at the appropriate maintenance elements and as a test access point to make a variety of manual transmission tests. These access lines are potential facilities as a fault report po
17、int (circuit) or fault report point (network) and/or testing point (transmission). Separate access codes will be allocated for each of the access line types described below. This is to ensure that if an Administration wishes to separate the various maintenance functions (i.e. transmission testing, s
18、witching testing and fault reports) it can do so. These allocations should not, however, stop those Administrations that wish to combine one or more of the functions, using a single access code. 1.3.1 Transmission access test lines The transmission access test line is a dialable test line intended t
19、o be located at the circuit maintenance test position or test console location associated with the international switching centres. These test lines are expected to be used as a test access point to make a variety of manual transmission tests. They may also be used for voice communication purposes a
20、ssociated with the circuit testing. The proposed dialling plan for these test lines enables a particular test position or console to be selected when the distant switching centre is equipped for this type of dialling access, If the normal test position number (access code) is busy, it is expected th
21、at the call should route to an idle test position number via a hunting group. Generally, the allocation of access codes should allow the digits 21 (see 0 2.4.2) to cause the incoming test line call to route to the test position or maintenance console normally assigned to the particular circuit group
22、 over which the incoming call originated. Then the use of digits 22 to 29 (non CCITT No. 6 signalling) would allow the maintenance personnel to make a test line call to a specific test position or maintenance console at the distant location. This will ailow both flexibility in assigning the test pos
23、itions and consoles, and may also relieve the need for all test positions or consoles to be equipped with the same test equipment. 1.3.2 Other test andor communication lines A requirement exists for the provision of lines for manual switching and signalling tests and for the provision of facilities
24、for a fault report point (circuit) or a fault report point (network). Codes will be allocated to these lines when the requirements are fully defined. 1.4 Echo suppressor test line The echo suppressor test line is a dialable 4-wire test line intended to terminate the echo suppressor testing system (E
25、STS) responder on an intemational switching centre. This test line will allow the maintenance personnel at the distant switching centre using the ESTS director equipment to make one-man semi-automatic echo suppressor tests on the circuits between the two centres. For further information about the ch
26、oice of the test reference frequency, refer to Recommendation 0.6. 2 Recommendation 0.11 (10/92) CCITT RECMN*O.LL 92 4862591 0579194 749 The ATME No. 2 test lines are dialable 4-wire test lines intended to terminate the ATME No. 2 responders 1 (see Recommendation 0.22 6). The responding equipment is
27、 available in two forms: I 1.5 Loopback test line j a) a signalling system functional testing and transmission measuring device (type a); 1.5.1 Analogue loopback test line The loopback test line is a dialable 4-wire test line that initially returns a nominal 1020 Hz -10 dBmO tone for 13 to 15 second
28、s. After the initiai tone period, the test line should present a balanced 600-ohm termination to the “RETURN” direction for the next 13 to 15 seconds. The “GO” direction should also be terminated in a 600-ohm balanced termination during both these first two intervals. After the second interval, the
29、6OO-ohm terminations should be disconnected. Finally, the “Go” and the “RETURN” directions should be connected (looped around) in the test responder at the correct level until released by the calling station. The intent of this test facility is to provide a one-man manual means of performing fast tr
30、ansmission tests (level and noise) in both directions. It will also allow seizure and rapid testing by an automatic device at the calling station. 1.5.2 Digital loopback test line The digital loopback test line provides a dialable 4-wire test line capability intended both for use in measuring the er
31、ror performance of international digital circuits and as a quick method of verifying the continuity of wholly digital, non-PCM encoded and mixed analogue/digitai circuits. It consists of circuitry that accepts and loops back on a digital basis the signal from a circuit. The test signal may be any ar
32、bitrary digital test pattern or analogue test signal. Once the tester has accessed the test line at a remote location, the tester may transmit the desired analogue test signals or digitai test patterns. The tester may examine the returning signal for the received power (or continuity) of the analogu
33、e test signals or the error performance (or continuity) of the digital test patterns. The proposed dialling plan for this test line enables a particular line to be selected when the distant switching centre is equipped for this type of dialling access. If the normal test line number (access code) is
34、 busy, it is expected that the call should route to a busy indication. 1.6 Echo canceller test line The echo canceller test line is a dialable 4-wire test line intended to terminate the echo Canceller test responder. This test facility will allow maintenance personnel at the originating switching ce
35、ntre to make tests of the echo canceller(s) on the circuit under test. Whether the test will be made on both echo cancellers or just the echo canceller at the responder end of the circuit under test wiil depend on the type of directing equipment being used. 3 ! 1.7 AME No. 2 test lines b) a signalli
36、ng system function testing device (type b). The ATME No. 2 equipment, consisting of directing equipment at the outgoing end and responding equipment at the incoming end, is intended to make automatic transmission measurements and signalling system functional tests on all categories of international
37、circuits terminating in exchange with 4-wire switching. Recommendation 0.11 (10192) 3 CCITT RECMNrO.LL 92 = 4862573 0577375 685 1.8 Busy flash signal test line The busy flash test line is a dialable 4-wire test line intended for use with the ATME No. 2 directing equipment (see Recommendation 0.22 6)
38、. This test line, which is also referred to as type c responding equipment in Recommendation 0.22 6, is required in cases when the signalling system used on the circuits to be tested provides a busy flash signal. This test line functionality may be provided within the exchange equipment or by separa
39、te responding equipment. 2 Method of access 2.1 In general, access arrangements should conform to the Recommendation M.565 i. 2.2 switching equipment on a 4-wire basis on ail incoming and both-way circuits. Access to the test lines at the incoming international exchange will be gained via the normal
40、 exchange 2.3 The wiring loss build-out arrangements for the test lines should conform to the Recommendation M.565. 2.4 Address information 2.4.1 Address infonnation sequence The following address information will be used to gain access to the maintenance access lines at the i) incoming internationa
41、l exchange. CCIT Signalling System No. 4 a) terminai seizing signai; b) code 13; c) code 12; d) digit O; e) f) code 15. CCIT Signalling System No. 5 a) KP1; b) c) code 12; d) digit O; e) f) ST. iii) CCIT Signalling System No. 6 The initial address message format for access to testing devices is give
42、n in Recommendations Q.258 2 and Q.259 3. The X digit allocation should be as follows: a) b) c) two digits associated with the particular international test line type to be accessed (see 0 2.4.2); ii) digit 7 (non-allocated language digit); two digits associated with the particular international tes
43、t line type to be accessed (see 4 2.4.2); 1 (ATME No. 2 responding equipment type a for signalling tests and transmission measurements); 2 (ATME No. 2 responding equipment type b for signalling tests only); 3 (quiet termination test line); d) 4 (echo suppressor test line); 4 Recommendation 0.11 (101
44、92) CCITT RECMN*O.LL 92 ICI 4862593 0579196 511 m 2.4.2 e) 5 (loopback test line); f) g) h) 6.7 and 8 (transmission access test line). (See Note); 9 (echo canceller test line); 10 (digital loopback test line). Nute - The allocation of the X digit is under the responsibility of Study Group XI. In Sig
45、nalling System No. 6, the bits of the access codes (bit pattern) sent on the line need not be identical with the actual access code number used by the maintenance staff. As Signalling System No. 6 will mainly be used together with SPC exchanges, it will be possible to translate any access code into
46、an appropriate bit pattern. iv) CCIT Signalling System No. 7 a) b) code 13; c) d) code 15 (on request). test call indicator in the initial address message as given in Recommendation Q.722 4; two digits associated with the particular international test line type to be accessed (see 4 2.4.2); v) CCIT
47、Signalling System RI a) m; b) c) ST. digits to be agreed upon between the Administrations concerned; vi) CCIT Signalling System R2 a) test call indicator; b) codeI-13; c) two digits associated with the particular international test line type to be accessed (see 0 2.4.2); d) code 1-15 (on request). T
48、est line codes for CCIT Signalling Systems No. 4, 5, 7 and R2 i) ATME No. 2 responding equipment type a ii) ATME No. 2 responding equipment type b iii) Busy flash signal iv) quiet termination v) echo suppressor vi) analogue loopback . vii) digital loopback viii) multiple address capability for trans
49、mission access test line . ix) echo canceller test line . . 3 Specifications for the test line apparatus 61 62 63 64 65 66 68 2 1-29 67 The following specifications apply to all test line types unless otherwise noted and apply over the range of climatic conditions specified in Recommendation 0.3 7. Recommendation 0.11 (10/92) 5 CCITT RECMN*O.LL 92 Li862593 0579397 458 H 3.1 3.2 3.3 3.4 3.5 3.6 Tone source characteristics (quiet temination ana loopback test lines) a) The nominal tone source frequency should fall within 1004 to 1020 Hz. The tone source
