Electra Elite IPK II Document Revision 4C
Digital Trunk Clocking 2 - 301
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.
Figure 2-7 Digital Trunk Clocking Example 5
Figure 2-8 Digital Trunk Clocking Example 6