Nortel Meridian 1 Option 11C Manual page 67

Types of synchronization
Clock synchronization can be either tracking on the primary or secondary
reference clock or free run (non-tracking). In LD 73 (prompts PREF and
SREF), the DTI/PRI which supports the clock controller daughterboard is
defined as the primary clock reference.
Another DTI/PRI may be defined as the secondary clock reference. The clock
controller will synchronize from the primary or secondary's incoming pulse
stream. The clock controller will in turn supply clocking to all the other
DTI/PRI loops.
DTI/PRI hardware detects frame slips in tracking and free run modes. For
tracking mode, running the midnight routines prints the number of overflows
and clears the counter. For free run mode, running the midnight routines
prints the number of frame deletions and repetitions and clears the counters.
Tracking mode
There are two thresholds set in LD 73 as described in the table below.
Refer to Figure 8 on page 68 also.:
Prompt Response
SRTK 1-(5)-24
1-(30)-3600
DTI/PRI Maintenance
Description
Slip rate maintenance (in hours) and out-of-service
threshold (per hour).
These are the frame slip rate thresholds for the tracking
mode. The first value is the maintenance threshold; the
elapsed time (in hours) in which 2 frame slips occur
(default is two slips in five hours). The second value is
the out-of-service threshold; or the number of slips
allowed in one hour (default is 30 slips in 1 hour).
When a threshold is reached, a DTA messages is output
as follows:
DTA015:Frame slip --- tracking --- maintenance limit.
DTA016:Frame slip --- tracking --- out of service limit.
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