NEC UNIVERGE SV9100 Features And Specifications page 350

Digital Trunk Clocking Example 3
In this example, there are multiple T1 circuits in the system. There can only be one T1 circuit assigned
as EXTERNAL in the system, so the T1 assigned as EXTERNAL is the PLO synchronization source.
Digital Trunk Clocking Example 4
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.
Digital Trunk Clocking Example 5
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 Example 6
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