Chapter 4: EIU maintenance 109
indicators drive “fault thresholds” that trigger maintenance actions when exceeded.
•periodic functional audits to ensure that the hardware still functions
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The EIU hardware diagnostics do not extend beyond the EIP (NT9X85). Any faults in the AUI, MAU, or network are not necessarily detected by EIU diagnostics.
Manual system maintenance
Maintenance personnel and engineers can manually maintain the EIU and related hardware in the same way that they maintain all
•commands are used to put the node into a variety of states (for example, OFFL and MBSY
•problems on the node trigger automatic maintenance actions and raise alarms that notify maintenance personnel that a problem exists
Maintenance activities includes the following:
•Alarm clearing. Alarms are displayed along the top of the MAPCI hierarchy. For information and procedures, refer to Alarm Clearing and Performance Monitoring Procedures,
•Troubleshooting. Maintenance personnel carry out troubleshooting procedure to try and isolate intermittent or difficult to trace problems. For information and procedures, refer to Trouble Locating Procedures, 297-
•Recovery. Maintenance personnel and engineers undertake recovery procedures after a component,
•Routine maintenance. Maintenance personnel use routine maintenance procedures to perform specific sets of tasks that the
•Card replacement. Maintenance personnel use card replacement procedures in two situations:
—as part of other maintenance procedures, required as a response to alarms or to complete trouble locating
—during routine card replacement