NEC Electra Elite IPK II System User Manual page 325

Electra Elite IPK II
In this example, there are multiple T1 circuits and a BRI circuit. Since the T1 assigned as EXTERNAL
has higher priority than a BRI, the T1 EXTERNAL is the PLO synchronization source.
In this example, there is a PRI, multiple T1s, and a BRI. The PRI was the PLO synchronization source
until it went down. The BRI then becomes the PLO synchronization source because when a PRI is in the
system, T1s cannot be assigned as EXTERNAL, which are not in the PLO Synchronization Source
priority list.
Digital Trunk Clocking
Figure 2-7 Digital Trunk Clocking Example 5
Figure 2-8 Digital Trunk Clocking Example 6
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