Tran:3512 DSU/CSU User`s Manual:Ch8:Test&Troublesh
Contents
1. 8 18 Testing and Troubleshooting 8 1 Chapter 8 Overview This chapter helps you troubleshoot problems in your 3512 DSU CSU or data communications network It provides tests and quick checks to solve problems that have simple causes Step by step fault isolation procedures help you locate problem causes by running tests from the 3512 front panel Table 8 1 provides a guide to these procedures NOTE Most tests disrupt data flow warn anyone affected at your site and the remote site before testing Table 8 1 Troubleshooting and Testing Guide If Do This Your data communications system is not transmitting and receiving correctly Your newly installed 3512 passes the Installation Checkout in Chapter 2 but does not operate correctly Your newly installed 3512 SDC passes the Installation Checkout in Chapter 2 but does not operate correctly Your 3512 is properly installed and was satisfactorily transmitting and receiving data before symptoms appeared Problems persist The Customer Support Center instructs you to return the 3512 to Motorola See Troubleshooting Sequence in this chapter refer to Chapter 2 for instructions on running the Automatic Self Test Refer to Quick Checks in this chapter Refer to Quick Checks in this chapter Refer to Troubleshooting Sequence in this chapter In the U S call the Motorola Customer Support Center Outside the U2. 3 Latching loops which continue looping until explicitly stopped prevent your applications from operating on the network Scrambler is designed to prevent the inadvertent transmission of data patterns that match loopback triggering patterns in 64k CC mode Refer to the Scrambler parameter description in Chapter 4 for important details Testing and Troubleshooting 8 13 Pattern Tests Pattern test options let you to specify the data pattern in loopbacks a DTE test device on a DTE port or internal pattern generator supply the data Figure 8 7 Pattern aa Tx Tx Rx N Figure 8 7 Pattern Test The pattern test is an aggregate level test even if DTE Config BitSteal or Muxed the 3512 sends the pattern over the entire DDS main channel at the full main chan nel port rate An Out of Sync alarm occurs at the remote unit that is not in pattern test if its DTE Config BitSteal or Muxed NOTE To run the pattern test in conjunction with the Remote Loop 2 initiate the Remote Loop 2 before the pattern test This lets the loopback signaling reach the remote unit undisturbed by the pattern data after the test terminate the pattern test before terminating Remote Loop 2 To run pattern tests 1 Display the menu 2 Press a until PATTERN TESTS displays Use mmm to display parameters Pattern Default Off Options Off On Description When set to On the selected pattern type is transmitt
3. Loopback Tests This section describes the loopback tests available for the 3512 Figure 8 1 Loopback tests can be initiated from the 3512 front panel or from an NMS NOTES 1 Disable System Status and Circuit Assurance when running loopback tests Loopback conditions can cause Idle signals to be received at one end of the circuit thereby activating the System Status or Circuit Assurance functions and inhibiting data from passing once the loopback is terminated 2 The local unit is the one that initiates the loopback test From the TEST menu press s so LOOPBACKS displays Press mmm to select the loopback tests described next Terminal Loopback Loop 1 Loop 1 Default Off Options Off port number Description Initiated by a local 3512 or 3512 SDC this command loops data from its DTE back to the DTE Figure 8 2 without passing it through the 3512 s transmit and receive circuitry P1 through P4 specifies the DTE port Terminal loopback examines the EIA interface between the 3512 and DTE The local DTE must be transmitting data during this test When operating in any Muxed mode this test interrupts data only on the port under test When operating in Multipoint Muxed mode If the loopback is initiated on a master device port the multipoint application on all slaves for that port is affected If the loopback is initiated on a slave device port only the application running on that slave
4. NOTES 1 A 3512 running BER Pattern or Loop 3 tests does not respond to an RT request Terminate tests in progress before you execute loops 2 An RT loopback test on the restoral line disrupts primary line data An RT on the primary line does not disrupt restoral line data 8 12 Testing and Troubleshooting DSU LLB Latching Loopback Test The provider initiates the LLB Loopback test by sending a special loopback sequence to the 3512 or 3512 SDC This test is available with 64k CC service In Multipoint Muxed modes On a master device an RT loopback interrupts data on all ports Slaves lose synchronization and transmit idle characters When the loopback is removed the master initiates a retrain sequence with all slave devices On a slave device only the data for that slave is interrupted The master detects that the slave is not responding attempts to initiate a retrain and if unsuccessful drops the slave from its active list of slaves Communication with other slaves however is still possible When the loopback is removed the slave signals the master to retrain it NOTES 1 The 3512 does not respond to LLBs on the inactive line while it is transmitting data on the active line Refer to the RT or DSU parameter description in Chapter 4 for important details 2 Ifa 3512 is running BER Pattern or Loop 3 tests it does not respond to an LLB request Terminate tests in progress before you execute loops
5. select number of bits to test Press NOTE The number of bits selected and the data rate determine the test duration Table 8 3 5 Press mas until BER Off displays Press so that BER On displays 6 Press to initiate the test Table 8 3 BER Test Duration Data Rate kbps 10 4 2 4 4 4 8 2 sec 9 6 1 19 2 0 5 56 0 0 2 BER Length Parameter Option 10 5 10 6 10 7 42 6 min 56 sec 69 min 40 sec 21 sec 3 min 28 sec 34 min 43 sec 10 sec 1 min 44 sec 17 min 22 sec 5 sec 52 sec 8 min 41 sec 2 sec 18 sec 2 min 58 sec NOTE For line BER tests allow an additional 30 seconds for initiation and termination of the test Table 8 4 shows the BER messages that can display Table 8 4 BER Messages LCD Display Definition BER PASS Unit passed test BER FAIL Unit failed test TEST RUNNING Test is running BER SETUP FAIL Test failed to run In xxx Test detected xxx inbound errors Out xxx Test detected xxx outbound errors 8 16 Testing and Troubleshooting Retrain Test The OTHER category contains the Retrain parameter Figure 8 1 OTHER displays only when DTE Con MPx Muxed where x master slave Retrain Default Off Options On Off Description This test initiates a retrain sequence If initiated at the master device the master initiates training If initiated at the slave the slave signals the master to initiate traini
6. S contact your nearest Motorola distributor Refer to Return Procedures at the end of this manual 8 2 Testing and Troubleshooting xTEST Menu Figure 8 1 shows the TEST main menu san LOOPBACKS Loop 1 PRIM Loop 2 RM Loop 2 Loop 4 Off Off Off Pn RT Pattern Type TESTS Off Space On Mark Alt 0 1 511 lt BERTESTS TESTS Test Type gt Address BER Length p BER Device 000 250 10 4 Off gn Line On OTHER Retrain a P The OTHER category appears only if the MP Mux feature is selected Figure 8 1 gt TEST Main Menu Troubleshooting Sequence This sequence is organized to help you isolate the problem By testing sections of your network in sequence you can eliminate areas and narrow down the problem Begin with Quick Checks Testing and Troubleshooting 8 3 Quick Checks The following steps may help you solve simple problems 1 Check all cable connections Review Installing the Standalone 3512 in Chapter 2 to verify that you have installed the cables correctly 2 Power down the unit and then power it back up This initiates the sel
7. 12 and loops it back without passing it through the local 3512 s transmit and receive circuitry Figure 8 6 This process examines the transmission facility the remote 3512 s circuitry and the remote EIA interface The Loop 4 test is not supported in Multipoint Muxed DDS II SC or 64k CC modes To run a Loop 4 first put the master and slave in Normal mode Since the loop tests the line as well as the device hardware the results of the test are valid regardless of the operating mode selected This test is similar to AT amp T specified LL also known as CSU loopback tests The ST LED flashes green during this test NOTE Set Timing Network MODIFY DSU before running this test om Tx X r om Jon Rx Tx Jone All ports All ports DDS line Local Remote Figure 8 6 Local Loopback Loop 4 Testing and Troubleshooting 8 11 Service Provider Telco Initiated Loopback Tests Service provider initiated loopback tests are performed at circuit installation or when trouble is reported to the provider CSU Loopback Test The provider initiates the CSU also known as LL loopback test by reversing the direction of the local loop sealing current on the 3512 or 3512 SDC In Multipoint Muxed modes When the master device is in the LL loop the LL loopback test interrupts data on all ports The slaves lose synchronization shut down their ports and transmit idle characte
8. Chapter 8 Testing and Troubleshooting Contents pias ook eictielags 8 2 KTEST Ment 8 3 Troubleshooting Sequels am vapeur Cain va 8 3 ETES ar basecd bispecdbioneateees 8 4 Common 8 5 Running Tesis a 8 6 Froni the Front Panel IE E Ea ATI Eein 8 6 From the Network Management System NMS 8 6 Loopback Toe ise es peep ety Su T 8 7 8 7 8 8 Remote Loopback Loop 2 8 9 Fass cpr vino cap aces Seve tates R 8 10 Local LoophackMLoop inesvniceosnsstinevsiseowvesiods 8 11 Service Provider Telco Initiated Loopback Tests 8 12 CSU Loopback Test 8 12 DSU RT Non Leichnie Loopback Test 8 12 DSU LLB Latching Loopback Test 8 13 adn natn 8 14 Emor Rate BER Tests 8 15 eden ulate E Clyne 8 15 Device BER Measles 8 15 Initiating a Line ar Device BER Tesh 8 16 Retrain Test 8 17 Correcting Port Interference Problems 8 17 If You Cannot Isolate the
9. ed in place of DTE data and the receive data is monitored for the pattern Each time an error in the pattern is detected the ST LED flashes red Type Default Space Options Space Mark ALT 0 1 511 Description This parameter specifies the pattern to be transmitted and received Space Only Spaces are transmitted Mark Only Marks are transmitted ALT 0 1 An alternating Mark Space pattern is transmitted 511 Pseudo random 511 Bit Pattern is transmitted 8 14 Testing and Troubleshooting Bit Error Rate BER Tests There are two BER performance tests available for the 3512 DSU CSU Line BER tests the line e Device BER tests the 3512 s internal circuitry NOTE BER tests interrupt user data Line BER Line BER is an end to end pattern test between local and remote 3512s The number of outbound local to remote and inbound remote to local errors is reported NOTES 1 In Multipoint Muxed mode initiate this test only at the master device Slaves not in test stop transmitting until they receive a retrain signal from the master 2 Disable System Status and Circuit Assurance MODIFY main menu MODIFY PORT category before running line BER tests These tests can activate those functions 3 Line BER tests are not supported when Opmode 64k CC and DTE Con Normal 4 When running a Line Bit Error Rate LBER test initiated from a network manager do not run a 10 b LBER if the 3512 is operating at 2 4 kb
10. f test which is explained in Chapter 2 If the unit fails the test the ST LED turns steady red and an alarm message displays in place of the default display check for alarm conditions under the STATUS menu Chapter 5 If you cannot resolve the problem there may hardware failure in the local unit Contact Motorola Customer Support and provide the information listed under Motorola Customer Information That section is located towards the front of this guide following About This Man ual 3 Using the appropriate configuration worksheet Appendix C as a guide go through the configuration menus to ensure that the 3512 or 3512 SDC is configured appropriately for the current application 4 On 3512 SDCs a Set both units to P3 Direct Determine whether the units communicate If eThey do not contact Motorola Customer Support providing informa tion as described in Step 2 do go on to the next step b Set both units to P3 Compress set one unit to Compress Mode Answer and the other to Originate If the units do not communicate check the alarm queue display for Link alarms elf any are shown contact Customer Support providing information as described in Step 2 elf there are no Link alarms go on to the next step Set both units to Format NRZI If the units do not communicate eDetermine whether DTEs support the port rate to which the 3512 SDCs are set Data Rate parameter eDetermine whe
11. is affected other slaves can respond to the master The ST LED flashes green during this test AZ X Tx A a Local Signal Stops Figure 8 2 Terminal Loopback Loop 1 Testing and Troubleshooting 8 7 Digital Loopback Loop 2 Loop 2 displays as PRIM Loop 2 when in restoral Default Off Options Off RT port number Description This command initiates a digital loopback test Loop 2 display Initiated by the local 3512 Loop 2 disconnects the 3512 from its DTE Data from the remote DTE is passed through the local 3512 s receive and transmit circuitry and looped back to the transmission facility and the remote DTE Figure 8 3 PRIM Loop 2 display When the device is operating on the restoral line this mode lets the device execute an RT loop on the primary line without disrupting restoral line data Both displays in any Muxed mode this test interrupts data only on the port under test In Multipoint Muxed mode e If the loopback is initiated on a master device port the multipoint application on all slaves for that port is affected If the loopback is initiated on a slave device port only the application running on that slave is affected other slaves can respond to the master Pn Activates the Loop 2 test for the specified port only Other data such as framing or the secondary channel is unaffected This option does not display when the parameter display i
12. ng Correcting Port Interference Problems If equipment connected to your 3512 that drives Pins 14 or 23 in EIA 232 operation causes electrical interference you can correct the problem by isolating those pins from one another You do this by adjusting the 3512 s internal Mux option card Dual Inline Package DIP switches NOTE DIP switches are set to On at the factory and must be On to support V 35 operation To change DIP switches 1 Remove the 3512 enclosure cover as described in Chapter 2 and set it aside Note the DIP switches at the rear of the option card in two groups of four Figure 8 8 Caution Components used in the 3512 DSU CSU are sensitive to static electricity discharge which can damage the 3512 s internal components Use proper handling and grounding precautions when handling the 3512 card or components Testing and Troubleshooting 8 17 Left 123 4 Right 123 4 Figure 8 8 EIA 232 V 35 DIP Switches Facing the rear of the 3512 from left to right the switches are as follows Switch No Port Switch ON Connects Switch OFF Isolates 4 in left group None 3 in left group None 2 in left group 2 Pin 2 to Pin 14 Pin 2 from Pin 14 1 in left group 2 Pin 23 to Pin 24 Pin 23 fr
13. om Pin 24 4 in right group 3 Pin 2 to Pin 14 Pin 2 from Pin 14 3 in right group 3 Pin 23 to Pin 24 Pin 23 from Pin 24 2 in right group 4 Pin 2 to Pin 14 Pin 2 from Pin 14 linright group 4 Pin 23 to Pin 24 Pin 23 from Pin 24 V 35 operation requires that the port s DIP switch is set to ON 2 Set the appropriate switches OFF For example to correct interference on Port 4 set switches 1 and 2 on the right bank OFF 3 Replace the 3512 enclosure cover 4 Replace the cables on the rear panel If You Cannot Isolate the Fault If you are unable to resolve the problem and need technical assistance contact the Motorola Customer Support Center or distributor The telephone numbers are listed under Motorola Customer Information which follows About This Manual Also in that section is the information to provide when calling so the representative can assist you promptly If you are advised to return the unit to Motorola refer to the Return Procedures section towards the end of this guide 8 18 Testing and Troubleshooting
14. ps 5 When running LBER tests between a 3512 and 3500 DSU CSUs with revision 3 2 software Front panel initiated tests function properly only when initiated from the 3500 Network management initiated tests function properly from either device but for DDS line rates of 19 2 kbps and below limit the length to 10 b IMPORTANT Motorola recommends running BER tests from the network manager if one is attached because received network management polling data may cause false error readings at 3512 units Device BER The device BER test places only the local unit in loopback It loops a test pattern through the transmit and receive circuitry of the unit and checks the pattern for errors The line connection is maintained however the transmit signal level is set to 0 NOTE In MP Mux mode a DBER functions as a DSU Check Loop 3 does Testing and Troubleshooting 8 15 Initiating a Line or Device BER Test To begin a BER test refer to Figure 8 1 1 From the main menu press a until BER TESTS displays 2 Press until Test Type displays Press to select Line or Device 3 When initiating a device BER test skip this step For a line BER test press mmm until BER Address displays Use the numeric entry procedure Chapter 3 to identify the unit s BER Address a remote unit the NC Address Press 4 Press mma until BER Length 10 4 displays 10 4 represents 10 10 000 bits Press
15. rs When the loopback is removed the master initiates a retrain sequence with each slave If the loopback is initiated on a slave only the data for that slave is interrupted The master detects that the slave is not responding attempts to initiate a retrain and if unsuccessful drops that slave from its active list of slaves Communication with other slaves is still possible When the loopback is removed the slave signals the master to retrain it NOTE This loop is supported in restoral The 3512 transmits on the dial line while the test is in process Since this test is non disruptive it is preferable to an RT test DSU RT Non Latching Loopback Test The provider initiates the DSU RT Loopback test by sending a special alternating loopback sequence to the 3512 or 3512 SDC This test is available with DDS I DDS II SC and SW 56 services In Multipoint Muxed modes On a master device an RT loopback interrupts data on all ports Slaves lose synchronization and transmit idle characters When the loopback is removed the master initiates a retrain sequence with all slave devices On a slave device only the data for that slave is interrupted The master detects that the slave is not responding attempts to initiate a retrain and if unsuccessful drops the slave from its active list of slaves Communication with other slaves however is still possible When the loopback is removed the slave signals the master to retrain it
16. s PRIM Loop 2 RT Remote Terminal Performs the Loop 2 test for all received data This setting is not recommended in MP Muxed configurations because it affects all ports and thus all applications This test is similar to AT amp T specified RT also known as DSU loopback tests The ST LED flashes green during this test C Tx Rx on J ore Rx j Tx Jom Local Sista Stops Remote Figure 8 3 Digital Loopback Loop 2 8 8 Testing and Troubleshooting Remote Loopback Loop 2 Rm Loop 2 Default Off Options Off port number Description This command initiates a remote digital loopback test Initiated by the local 3512 this command disconnects the remote unit from its DTE During this test data from the local 3512 is passed to the transmission facility through the remote unit s receive and transmit circuitry and looped back to the local unit Figure 8 4 In this example Port 4 on the local and remote units is under test Pn This option activates the Loop 2 test for the specified port only Other data such as framing or the secondary channel is unaffected The ST LED flashes green during this test NOTES 1 Remote Loop 2 is not supported in multipoint environments In multipoint or multi tier environments additional devices may receive the loopback signaling and go into loopback 2 Set Timing Network MODIFY DSU before running this
17. test 3 To run the pattern test in conjunction with the Remote Loop 2 test initiate the Remote Loop 2 test before the pattern test This lets the signaling that initiates and terminates loopback reach the remote unit undisturbed by the pattern test data When finished testing terminate the pattern test before terminating Remote Loop 2 om PA Tx Rx p4 Rx 4 X P4 Local _ Signal Stops Remote Figure 8 4 Remote Loop 2 Testing and Troubleshooting 8 9 DSU Check Loop 3 Loop 3 Default Off Options Off On Description Initiated by the local 3512 this command directs the local 3512 to loop data from its DTE through the 3512 and back to the DTE Figure 8 5 The line connection is maintained but the transmit signal level is set to 0 During DSU Check data from the DTE passes through the 3512 s transmit and receive circuitry and back through the interface to the DTE The ST LED flashes green during this test NOTE This test interrupts user data When the 3512 is in a Muxed mode all Muxed ports are affected Local Figure 8 5 DSU Check Loop 3 8 10 Testing and Troubleshooting Local Loopback Loop 4 Loop 4 Default Off Options Off On Description Initiated by the local 3512 this command disconnects the local 3512 from its DTE During the test the local 3512 receives data from the remote 35
18. ther the support clock stopping which the 3512 SDCs use d If none of these actions resolve the problem contact Customer Support as described in Step 2 If these checks do not solve the problem run the diagnostic tests below 8 4 Testing and Troubleshooting Isolating Common Problems IMPORTANT Motorola recommends running bit error rate BER tests from the network manager if one is attached This is because received network management polling data used when running BER tests from the front panel in a network man aged system may cause false error readings at 3512 units For each pair of devices run the BER and Loopback tests in the following sequence NOTE For instructions on initiating BER and Loopback tests refer to the next section Running Tests 1 If you are running the test from a network managed 3512 s front panel set both the local and remote NC Override parameters to On 2 Initiate a device BER test for each 3512 If either unit fails the problem is in that unit If both units pass go to Step 3 3 Initiate a line BER test If the line fails check that the units are configured for the correct digital service and speed If they are the problem is most likely with the transmission facility If the test is passed go to Step 4 4 Run the appropriate loopbacks refer to Loopback Tests to further isolate the problem The problem is probably between the 3512 and the data terminal eq
19. uipment DTE Testing and Troubleshooting 8 5 Running Tests Tests to identify operating problems can be run from the front panel or from a Network Management System NMS to all local and remote 3512s on the circuit IMPORTANT The only test supported in restoral are the service provider initiated local loopback and the Primary Loop 2 From the Front Panel To start a test from the front panel use the front panel keys as described in Table 8 2 Refer to Figure 8 1 to identify your location in the menu tree During a test the ST LED flashes green Table 8 2 Test Sequence Press Until this Displays TU TEST p LOOPBACKS PATTERN TESTS or BER TESTS TEST SELECTED Off TEST SELECTED On TEST SELECTED On NOTE Configuration changes cannot be made while a test is running To stop a test 1 Display TEST SELECTED On 2 Press to display TEST SELECTED Off 3 Press From the Network Management System NMS When the 3512 DSU CSU is operating under network control tests must be initiated from the NMS If you attempt to initiate a test from the front panel the message NC ATTACHED displays To disable network control set NC Override On at both the local and remote units MODIFY main menu MODIFY NETWORK category The tests can then be run from the 3512 front panel After testing restore network management control by set ting NC Override Off 8 6 Testing and Troubleshooting
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