Sync (Synchronization) - Avaya Definity SI Maintenance Manual

Maintenance Object Repair Procedures

SYNC (Synchronization)

MO Name (in
Alarm Log)
SYNC
SYNC
SYNC
The Synchronization Maintenance is composed of both hardware and software
components and its purpose is to provide a common reference frequency for
reliable digital communication between systems and other PBXs, COs or CPE.
Synchronization is achieved via the use of several system components which
include the Tone-Clock, the DS1 Interface, and the Expansion Interface circuit
packs. Synchronization is achieved between the PPN and the EPNs via the
Expansion Interface Link (EXP-LINK) between the networks.
Depending on the network synchronization plan and the status of synchronization
sources, the system timing reference may be a Tone-Clock circuit pack, DS1
interface circuit packs or an external Stratum 3 clock. Stratum 4 synchronization
extracts timing information directly from a DS1 reference or from a Tone-Clock.
Stratum 3 synchronization requires the use of a Stratum 3 clock which provides a
timing signal, derived from DS1 references, to the TN780 Tone-Clock circuit pack.
The external Stratum 3 clock is a more stable timing source than the Stratum 4
clock and provides 24-hour holdover in case of reference failures. The Stratum 3
clock has redundant components.
Stratum 4 Synchronization
The system can be configured with primary and secondary synchronization
references (DS1 interface circuit packs) when using Stratum 4 synchronization.
Both references are optional (since the local oscillator can be used), and the
secondary reference is optional if a primary is provided. If this system is the
master for the network, then its local oscillator would be used and no DS1s would
be used as references.
If the primary synchronization reference is not providing a valid timing signal, the
system automatically switches to the secondary synchronization reference. If the
secondary reference does not provide a valid timing signal or is not administered
as a synchronization reference, a Tone-Clock circuit pack provides the system
timing source. The system does not revert to the primary if the current reference is
the secondary and is failing; however the system switches from the local oscillator
to another reference when the new reference becomes available. The following
diagram should assist in understanding Stratum 4 Synchronization Maintenance
components within the system. This diagram depicts a possible Generic 1.2
configuration; DEFINITY Generic 1 does not support two EPNs, but the operation
and maintenance described below is the same except for the references to
multiple EPNs.
10-1586 Issue 4 May 2002
Alarm Initial Command to
Level Run
MAJOR display errors
MINOR display errors
WARNING test synchronization
Full Name of MO
Synchronization Maintenance
Synchronization Maintenance
Synchronization Maintenance
555-233-123