Lucent Technologies MERLIN LEGEND Release 7.0 Feature Reference page 605

MERLIN LEGEND Communications System Release 7.0
Feature Reference 555-670-110
Features
Primary Rate Interface (PRI) and T1
Table 36.
Entry
Service
Expected Digits
Example #
Digit deletion
Digit addition
Extension
Systemwide Programming Options
Clock Synchronization
Clock synchronization is an arrangement in which digital facilities operate from a
common clock. Whenever digital signals are transmitted over a communications
link, the receiving end must be synchronized with the transmitting end to receive
the digital signals without errors.
The system synchronizes itself by extracting the timing signal from the incoming
digital stream. If the system has one 100D module, that module provides its own
primary synchronization. If the system has at least one 800 NI-BRI module, more
than one 100D module, or a combination of 100D modules and 800 NI-BRI
modules, then one of the connections provides primary clock synchronization for
all 800 NI-BRI and 100D module ports and for the system's time-division
multiplexing (TDM) bus. The primary clock synchronization source must be
identified during system programming. The factory setting either is the first 100D
module or the first port on the first 800 NI-BRI module in the carrier. This can be
changed through system programming.
In the event of a maintenance failure of primary synchronization, backup
synchronization can be provided by secondary and tertiary clock synchronization.
In addition, the source of synchronization is factory-set to Loop Clock Reference
Source so that the clock is synchronized to the outside source. With a 100D
module, it can be set to Local Clock Reference Source so that the clock is
free-running. This is not recommended, however, for most permanent installations
or for systems with PRI. This setting must be made for the primary, secondary,
and tertiary synchronization sources.
Sample T1 Switched 56 Dial-Plan Routing Table
1 2
T1 S56 T1 S56
3 3
234 235
1 1
[none] [none]
34 35
3 4...
T1 S56
3
300
1
67
6700
Issue 1
April 1999
545
24
T1 S56
3
492
1
69
6992