Nortel Meridian 1 Option 11C Manual page 73

If a loss of frame alignment condition persists for three seconds, the affected
DTI/PRI card is taken out of service and a red alarm (local alarm) is raised.
See Figure 12.
If the loss of frame alignment condition clears at least 15 seconds, the
DTI/PRI is automatically restored to service. The following DTA message is
generated:
DTA021
Figure 12
Loss of frame alignment
DTA 021--loss of frame alignment.
3
seconds
Alarm threshold recommendations for digital trunks
If a digital trunk is present in an IP Expansion cabinet, link outages due to data
network performance degradation between main cabinet and expansion
cabinet will cause alarms on the far end of the digital trunk. If link outages are
frequent, alarm thresholds on the far end may need to be increased to prevent
the trunk from being placed in a state requiring manual intervention to
recover.
Clock operation
The Option 11C system supports a single clock controller that can operate in
one of two modes: tracking or non-tracking (also known as free-run).
DTI/PRI Maintenance
Loss of frame alignment has persisted for 3
seconds.
DTA 022--loss of frame alignment
cleared
15
seconds
Page 73 of 100
Option 11C 1.5 Mb DTI/PRI