Bri Module And Clock Synchronization - AT&T MERLIN LEGEND Reference

M a i n t e n a n c e
BRI Module and Clock
Synchronization
The time-division multiplex (TDM) clock reference for the system can be a loop
source supplied by the CO, or a local source supplied by the MERLIN LEGEND
system during certain maintenance conditions and events. The 800 CO-BRI
module can be a local source of clock reference, and any Digital Subscriber
Line (DSL) port on the 800 CO-BRI module can be the point of a loop source.
If the 800 CO-BRI module is being used as the local clock source for the system,
or if one of the DSL ports is being used as the loop clock source, the
maintenance software searches for another clock source when the BRI module
or DSL port is busied out or reset. The software chooses the programmed
secondary clock source; if the secondary source is not available, it chooses the
tertiary clock source.
If no programmed clock sources are available, the software searches the system
from the first slot to the last in the following order:
The first 100D module or 800 CO-BRI module port found is used as the
1.
loop clock source.
Local clock source (first one found is used).
2.
Local clock on the Processor module; the software uses this clock as the
3.
system clock.
When the 800 CO-BRI module or DSL port is restored, the maintenance software
restores the module or port as the clock source if the module or port is a higher
priority clock source than the one currently running. For example, if the 800 CO-
BRI module is the primary clock source for the system, once the 800 CO-BRI
module is restored, the software transfers the system clock source back to the
800 CO-BRI module.

BRI Module and Clock Synchronization

6-13