NEC SL1100 - Figure 1-11 Digital Trunk Clocking Example 5; Figure 1-12 Digital Trunk Clocking Example 6; Figure 1-13 Digital Trunk Clocking Example 7; Figure 1-14 Digital Trunk Clocking Example 8

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.
Main KSU
Exp. KSU
T1/E1
BRI
T1/E1
Figure 1-11 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.
Main KSU
Exp. KSU
Exp. KSU
T1/E1
T1/E1
BRI
PRI
Figure 1-12 Digital Trunk Clocking Example 6
If multiple BRIs exist and no PRI or T-1 EXTERNAL exists, the system chooses the first BRI that
synchronized with the carrier. In this example, the BRI in slot02 synchronized with the carrier first and
became the PLO synchronization source.
Main KSU
Exp. KSU
BRIBRI
Figure 1-13 Digital Trunk Clocking Example 7
In this scenario, the PRI was the clocking source until it went down. There are no other PRIs, T1
(Externals), or BRIs in the system. The CPU now becomes the PLO synchronization source.
Main KSU
PRI
CPU
Figure 1-14 Digital Trunk Clocking Example 8
ISSUE 2.0
SL1100
Features and Specifications Manual 1-213
D