1、)45G134 2 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%2!0(94%,%2!0(G0G042!.3-)33)/./2!.):!4)/.G0G0 amended at New Delhi, 1960and Malaga Torremolinos, 1984)The CCITT,considering(a) that it is desirable that faults affecting communication between stations on international switching networks(e.g.
2、telex and gentex service) should be reported and cleared as quickly as possible;(b) that it is necessary to unify the essential action to be taken and methods to be employed for locating andclearing faults;(c) that, for this purpose, it is necessary to determine the essential testing equipment that
3、is to be provided atthe switching centres responsible for locating and clearing faults,unanimously declares the view1 That it is necessary to set up switching and testing centres (STCs), defined as switching centres equipped withmeasuring equipment for testing telex subscribers and public station li
4、nes and equipment and also telegraph channels.2 Each telex subscriber and each public station in the general switching service should have access to an STC forthe purpose of reporting faults and cooperating in tests.3 International switching and testing centres (ISTCs) are the STCs that are also int
5、ernational line-head offices.4 All STCs should be subscribers to the telex network, both for the purpose of receiving fault reports and forcommunication for maintenance purposes. They should also be provided with a telephone subscribers line.5 Each STC should be responsible for coordinating action i
6、n locating and clearing faults on all station linesconnected to the exchange and on all trunk circuits for which it is nominated as the controlling office. It should alsocooperate with other STCs in locating faults on connections established through two or more exchanges.5.1 It should carry out a pr
7、eliminary location of faults by finding out whether they affect channels, switching gearor apparatus. The faults are then accurately located by the engineers responsible for each part of the circuit and the STCcooperates with them for this purpose. It may assume the direction of the fault-locating p
8、rocedure should there bedisagreement between these services. Internationally, it is responsible to the STCs of other countries with which it hastelex connections.5.2 The organization of the liaison between the STC and the different technical services is shown in Figure 1/R.90.The STCs must check tha
9、t the performance given by the equipment involved in the switching service, i.e. VF channels,switching equipment and apparatus, is satisfactory.2 Fascicle VII.1 - Rec. R.906 The staff employed at STCs should be selected with a view to avoiding language difficulties and should beconversant with all t
10、ypes of telegraph equipment used in the switching network, i.e. automatic or manual switchingequipment, VFT equipment, telegraph machines and regenerative repeaters. The staff need not necessarily be fullycompetent to maintain all these items of equipment, but should have sufficient knowledge of the
11、m to be able to form anappreciation of the effect that faults on any of them may have on a switched connection. In addition, the staff of ISTCsshould have some general knowledge of the types of equipment used in the countries to which they are connected,particularly of the signalling conditions that
12、 will be encountered.7 Each STC should be provided with the following measuring equipment:a) 50-baud start-stop distortion meter;b) test transmitter for generating undistorted 50-baud start-stop signals;c) apparatus to measure the modulation rate of teleprinters at a distance;d) apparatus for measur
13、ing the speed and pulse ratio of dials, where appropriate;e) apparatus for measurement of the condition of direct current lines; for example, continuity, resistance,insulation.7.1 The arrangements for access to established connections for making test measurements should be such as not tocause interr
14、uptions or reduce the quality of transmission.Fascicle VII.1 - Rec. R.90 37.2 Considering that some Administrations have found it desirable to have available at the STC other items ofapparatus to expedite the clearing of faults, all Administrations are invited to consider the utility of these device
15、s,namely:a) apparatus for measuring teleprinter margin;b) recording distortion meters for testing established connections;c) apparatus for measuring continuously, periodically and automatically, the distortion on subscribers linesand apparatus.8 The following procedure for reporting, locating and cl
16、earing faults should be adopted.8.1 Faults should be reported to the STC concerned by the subscribers or operators who have experienced difficultyin operation. In the same way, it would be useful, in order to give the STCs a full picture of the situation, that themaintenance engineers should inform
17、them of faults noted during the periodic maintenance operations. Faults shouldpreferably be signalled by teleprinter, if their nature does not preclude this procedure.8.2 A reference number should be given by the STC to the subscriber or service notifying the fault. This numbercan then be quoted in
18、any subsequent inquiries as to the progress of fault clearance.8.3 On account of the difficulties that may arise in the detection of faults on the international section of acommunication (due to lack of knowledge of languages, etc.), care should be taken in each country to see that thenational secti
19、ons of the communication, including subscribers lines and apparatus, are not involved beforeapproaching the STC of the corresponding country.8.4 Complete holding of a connection that is reported to be faulty should be avoided.8.5 The STC notified of a fault should therefore begin by ascertaining tha
20、t it is not located in the national section ofthe communication and for this purpose should, if necessary, approach the other STCs of its country concerned in thecircuit. The STC of the distant country is then advised and, in turn, checks the national section routed over its network.The internationa
21、l section of the communication is not checked until the terminal national sections of telegraph circuitshave been definitely exonerated. The STCs in different countries will communicate with one another, either directly orvia their ISTCs, as determined by the Administrations concerned.8.6 If the tes
22、ts of the two local ends fail to reveal any fault conditions, the STC should report the fault to its ISTC,which will decide what further action, if any, is necessary. As a rule, isolated fault reports would not justify a test of alltrunk circuits on a route, and it would be assumed that the conditio
23、n giving rise to the fault would be cleared on thenext routine adjustment. If however, several fault reports were received, some of which might have been due to a faultycircuit on a particular route, then a special routine test of all the circuits on the route might be justified.8.7 In general, it i
24、s considered that the procedure will be broadly the same for manual, semi-automatic andautomatic systems.9 The abbreviations annexed below should be used in calls exchanged between services responsible for themaintenance of telegraph equipment.4 Fascicle VII.1 - Rec. R.90ANNEX A(to Recommendation R.
25、90)List of service abbreviations for maintenance of telegraph circuitsNo. Abbreviation Meaning30 bis BL Holding30 BL . . . SVP Please hold . . .2 BR TR . . . Bad transmission on . . .39 bis CCT . . . IN I have restored circuit No. . . .39 CCT . . . IN SVP Please restore circuit No. . . .38 bis CCT .
26、 . . OUT I have taken circuit No. . . . out of service38 CCT . . . OUT SVP Please take circuit No. . . . out of service43 CRD . . . The connection is released after selection on circuit No. . . .37 bis CSR I am receiving your calling signal8 DER CCT Circuit faulty51 DER REG Register does not operate
27、52 DER TAPE Your perforated tape is faulty33 DER VF . . . Fault on voice-frequency system . . .7 DERA Machine faulty9 DERPS Position equipment faulty10 DERR Fault now cleared64 DEVD Deviation of distributor speed at your end23 DEVS . . . Speed deviation is . . . %16 . . . DIS . . . The distortion on
28、 is . . . %62 DS . . . Distribution switched over to . . .25 EDIS . . . The transmitter distortion is . . . %1 ICI . . . Here is . . .53 bis LOOP . . . I have looped circuit . . .53 LOOP . . . SVP Please loop circuit . . .24 MAR . . . The margin is . . . %18 MEET . . . Meet me on circuit No. . . .50
29、 N IND I am not receiving your answer-back code40 N PER A I am not receiving your permanent start polarity signal41 N PER Z I am not receiving your permanent stop polarity signal66 NARQ . . . Multiplex . . . unprotected; please re-establish automatic request forrepetition (ARQ)31 bis NBL . . . Clear
30、ing31 NBL . . . SVP Please clear . . .27 NCFM . . . No call-confirmation signal on . . .26 NCS . . . No call-connected signal from . . .Fascicle VII.1 - Rec. R.90 511 NDER No fault found42 NPS I am not receiving your proceed-to-select signal28 OCC OCC. . . Permanent busy signal from . . .65 OPH . .
31、. Out of phase on system . . .46 PER A . . . Permanent start polarity on . . .48 PER A . . . SVP Please send permanent start polarity on . . .47 PER Z . . . Permanent stop polarity on . . .49 PER Z . . . SVP Please send permanent stop polarity on . . .29 PERC . . . Permanent call on . . .63 PH . . .
32、 Please phase system . . .34 bis Q DIS A Is there bias distortion (prolonged start polarity) on the received signals?35 bis Q DIS Z Is there bias distortion (prolonged stop polarity) on the received signals?13 QDIS . . . Please measure distortion on . . . and report result37 QRCS Are you receiving m
33、y calling signal?3 QREF Please give reference number4 QRES Please report result15 RAP . . . MNS I shall recall you in . . . minutes14 RAP . . . MNS SVP Please call me in . . . minutes5 REF . . . Reference number is . . .6 RES . . . Here is result of test on . . .55 RFC . . . I am receiving errors in
34、 5-unit code. Please check channel No. . . .70 RMUT . . . I am receiving garbled signals on multiplex channel . . . please check your7-unit code54 RQFS . . . Your repetition cycle transmission contains 7-unit code faults. Pleasecheck channel No. . . .59 RS . . . Reception switched over to . . .44 SI
35、G 1/1 SVP Please send 1:1 signals45 SIG 2/2 SVP Please send 2:2 signals61 SS . . . Storage switched over to . . .12 TESTD . . . SVP Please send test message with . . . % distortion on . . .67 TRAS . . . Please send alpha signal on multiplex channel . . .68 TRBS . . . Please send beta signal on multi
36、plex channel . . .60 TRS . . . Transmission switched over to . . .21 VERED Please check the transmitter distortion22 VERM Please check the margin20 VERS Please check the speed19 VERX . . . Please check subscriber No. . . .34 ZKWA . . . The received signals have . . . % bias (start polarity prolonged
37、)35 ZKWZ . . . The received signals have . . . % bias (stop polarity prolonged)32 ZOK I am receiving correctly17 ZSU Your signals are unreadable71 ZYA Cease traffic on all channels; send As on A channel for line-up6 Fascicle VII.1 - Rec. R.9069 ZYC Your transmitter is sending permanent ARQ56 ZYK . . . Your keying on channel . . . is affected; please check57 ZYM Change from single printer to multiplex36 ZYN Reduce the bias58 ZYP Change from multiplex to single printer
