1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 2 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%2!0(94%,%2!0(G0G042!.3-)33)/.-!).4%.!.#%G0G04%343G0G04/G0G0“%G0G0#!22)%$G0G0/54/.G0G0).4%2.!4)/.!,G0G04$-G0G03934%-3)45G134G0G0RecommendationG0G02 (Extract from the “LUEG0“OOK)NOTES1 ITU-T Recommendation
2、R.116 was published in Fascicle VII.1 of the Blue Book. This file is an extract fromthe Blue Book. While the presentation and layout of the text might be slightly different from the Blue Book version, thecontents of the file are identical to the Blue Book version and copyright conditions remain unch
3、anged (see below).2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both atelecommunication administration and a recognized operating agency. ITU 1988, 1993All rights reserved. No part of this publication may be reproduced or utilized in any form or by any
4、 means, electronic ormechanical, including photocopying and microfilm, without permission in writing from the ITU.Fascicle VII.1 - Rec. R.116 1Recommendation R.116Fascicle VII.1 - Rec. R.116MAINTENANCE TESTS TO BE CARRIED OUT ON INTERNATIONALTDM SYSTEMS(Melbourne, 1988)The CCITT,considering(a) the s
5、avings to be made by reducing interruption time on TDM links;(b) the importance of being able to determine responsibilities between the several parties who, of necessity areinvolved in maintenance questions for the networks;(c) the advantages of standardization regarding maintenance;(d) maintenance
6、loops are standardized in Recommendation R.115,unanimously declares the following:that when the quality of the TDM-Iink has deteriorated beyond the alarm limit or if the local muldex gives analarm, supplementary measurement should be performed. The following test and supervision methods can be used.
7、1 Testing and supervision of TDM systems1.1 Bit error rateThe synchronization bits are supervised and an error rate alarm is issued when the error rate exceeds a presetlimit, 103, 104or 105.1.2 Bit error counterAll synchronization bit errors shall be registered in a cyclic counter and it shall be po
8、ssible to read the value ofthis counter by command.1.3 Routine supervisionThe operation of the TDM equipment and maintenance channel should continuously be supervised by arepetitive test signal. An alarm is issued when a correct acknowledgement is not received for a specified number of testsignals.
9、The alarm is reset automatically when the fault situation ceases.1.4 Alarm resetIt shall be possible to reset all alarms from the local side. The command shall also be able to reset the error ratevalue.1.5 System alarmsFailures that affect operation of the whole or a major part of the TDM equipment
10、are classified as one category.The supervised functions are: Carrier:Loss of carrier is detected by the data modem through CCITT circuit 109 or the corresponding circuit. Synchronization:Loss of synchronization is detected by the TDM multiplexer in accordance with the respective CCITTRecommendation.
11、2 Fascicle VII.1 - Rec. R.116 Multiplexing logic:Failure of the TDM central logic is detected by internal supervision facilities within the multiplexer. Power:Failure of the power supply is detected when the telegraph power supply exceeds tolerance limits.1.6 Changing of active sideWhen the TDM equi
12、pment is duplicated the active side can be changed by command or manually.When the remote or local side is changed automatically or manually, information about what side is executivemust be sent when the change has been executed.1.7 Looptest on standby sideWhen the TDM equipment is duplicated the st
13、andby modem can be tested by the setting of loop b by command.The test result is sent over the active maintenance channel.1.8 Automatic restartWhen the remote TDM is automatically restarted, information shall be sent informing about the restart andalarm status.1.9 AcknowledgementThe acknowledgement
14、consists of one character and should have the following values:5 acknowledgement;0 not acknowledgement.2 Format of the messagesThe messages which will be sent over the 50 baud maintenance channel shall have the following structure:ClC2M1M2. . . . MnClC2:Message category (two characters)M1 Mn: Inform
15、ation (number of characters unlimited)After the reception of a message at the receiving end, the receiving end shall send one character to theoriginating end as an acknowledgement of the reception.2.1 Message categoriesThe purpose of the message categories (called MC) is to give a direct command or
16、to inform the controlequipment in an exchange, a maintenance centre or a TDM about what type of information the following messagecontains.The MC consist of two characters, and each character is a decimal number from 0 to 9. The numbers are codedaccording to alternative A (CSC) in Recommendation R. 1
17、15.2.2 InformationThe information characters are a part of an order to the remote TDM equipment or information from the remoteTDM-equipment, depending on the Message Category Signal.The number of information characters in a message is not limited.The characters are decimal numbers from 0 to 9, coded
18、 according to alternative A (CSC) inRecommendation R.115.3 Maintenance messagesUsing the format described in 2 the maintenance messages shall have a message category and information asgiven in the table below:Fascicle VII.1 - Rec. R.116 3TABLE 1Maintenance messagesTypes of messages Message category
19、InformationC1C2M1-MnRoutine supervision 01 System alarm reset 02 Setting of loop a 03 Setting of loop b 04 Setting of loop c 05 Setting of loop d 06 Setting of loop g 07 M1-M3: Channel No.Setting of loop h 09 M1-M3: Channel No.Setting of loop f 10 M1-M3: Channel No.Connection of automatic test eq. 1
20、1 M1-M3: Channel No.M4-M23: Answer back (See note)Disconnection of automatic test eq. 12 Distortion measurement on sub. line 13 M1-M3: Channel No.Line measurements 14 M1-M3: Channel No.M4: Type of line0 = SC1 = DC2 = FSM5: Type of measurement0 = Current1 = Voltage2 = Leakage to earth3 = Leakage betw
21、. conductors4 = Level FS5 = Interface testChange side 15 M1: Sideb0= 0 A side executiveb0= 1 B side executiveb1= 0 Standby side haltedb1= 1 Standby side workingRestart of control unit 16 Read bit error counter 17 Set loop b on remote standby side modem 18 Open line alarm 26 M1-M3: Channel No.M4: Ala
22、rmb0= 1 Alarmb0= 0 No alarm4 Fascicle VII.1 - Rec. R.116TABLE 1 (continued)Types of messages Message category InformationDistortion alarm 27 M1-M3: Channel No.Bit error rate 28 M1: Failure rate3 = 1034 = 1045 = 105Results of distortion measurement sub. line 29 M1 M2: Number of measured transitionsM3
23、 M4: Maximum distortionResult of line measurement 30 M1-M10: Test resultM1= 0 Level FS OKM1= 1 Level FS not OKM2= 0 Interf. OKM2= 1 Interf. not OKM3 M4: Voltage or current on wire 1 andresistance between wire 1 and 2.Resistance to earth, w.1M5 M6: Voltage or current on wire 2 or resistancebetween wi
24、re 3 and 4. Resistance toearth, w.2M7 M8: Voltage or current on wire 3. Resistanceto earth, w.3.M9 M10:Voltage or current on wire 4. Resistanceto earth, w.4System alarms 31 M1: Type of alarmb0= 1 Carrier alarmb0= 0 No carrier alarmb1= 1 Synchronization alarmb1= 0 No synchronization alarmb2= 1 Power
25、alarmb2= 0 No power alarmb3= 1 Mux logic alarmb3= 0 No Mux logic alarmManually initiated change side 32 M1: Sideb0= 0 A side executiveb0= 1 B side executiveb1= 0 Standby side haltedb1= 1 Standby side workingLooptest result from standby side 33 M1: Result0 Test OK1 Test not OKAutomatic restart 34Bit error counter 35 M1-M3: ResultNote The answer back message shall be sent using International Alphabet No.2.
