Clock Synchronization - AT&T MERLIN LEGEND Reference

System Programming

Clock Synchronization

The time-division multiplex (TDM) clock source in the MERLIN LEGEND system
provides the timing needed to synchronize the flow of digital transmission
between the central office (CO) and the system. Any 100D module or any port
on an 800 CO-BRI module can be the TDM clock source. On an 800 CO-BRI
module the clock source is loop source (taken from the 5ESS CO). The 800 CO-
BRI module can be the primary, secondary, or tertiary clock source. In general,
the primary clock should be the most reliable clock source available.
NOTE:
Both 100D modules and 800 CO-BRI modules can be programmed as primary,
secondary, and tertiary clock sources, but not simultaneously. For example, if a
100D module is programmed to be the secondary clock source, an 800 CO-BRI
module cannot be programmed as the secondary clock source.
The actual point on the 800 CO-BRI module for the loop clock source is one of
the ports (the Digital Subscriber Line port).
The following information must be programmed to assign the clock source on the
800 CO-BRI module:
The slot numbers of the 800 CO-BRI modules that serve as the primary,
secondary, and tertiary clocks
The number of the port used as the source
When the primary clock is programmed, it automatically is activated to serve as
the TDM clock reference for the system. Upon a "system erase," the first 100D
module or 800 CO-BRI module port found in the control unit from a sequential
search becomes the primary loop clock source. Upon a "system restart, " the
programmed primary clock acts as the TDM clock reference for the system.
Follow these procedures to program the 800 CO-BRI module to be a TDM clock
source for the MERLIN LEGEND system.
NOTE:
If possible, to minimize maintenance errors, all three clock sources should be
administered following the guidelines in Chapter 4.
Entering Programming
Console: Select
PC/SPM: Type SPM
Exiting Without Changes
To exit from any screen without making changes, select
Press F5
Clock Synchronization
5-6
Menu
Sys Program
Select any key F1
on the PC before saving your entry or menu selection.
Exit
F5
Exit on the console or