DEFINITY ECS Release 8.2 Maintenance for R8.2csi
555-233-119 Issue 1
April 2000
Maintenance Objects
3-1003SYNC (Synchronization)
3
SYNC (Synchronization)
The Synchronization Maintenance is compos ed of both hardware and software
components and its p urpose is to provide a common reference frequency for
reliable digital c ommunication between systems and other PBXs, COs or CPE.
Synchronization is achieved via the use of several system components whic h
include the Tone-Clock and the DS1 Interface.
Depending on the network s ynchronization plan and the sta tus of
synchronization sources, the system timing reference may be a Tone-Clock
circuit pack or DS1 interface circuit pac ks. Stratum 4 synchronization extracts
timing information direct ly from a DS1 reference or from a Tone-Clock.

Stratum 4 Synchronization

The system can be config ured with primary and sec ondary synchronization
references (DS1 interface circuit p acks) when using Stratum 4 sync hronization.
Both references are optional (since the lo cal oscillator can b e used), and the
secondary reference is op tional if a primary is p rovided. If this system is the
master for the network, then its local oscillato r would be used and no DS1s would
be used as references.
If the primary synchronization referenc e is not providing a valid timing signal, the
system automatically switches to the secondary synchronization reference. If the
secondary reference d oes not provide a valid timing signal or is not ad ministered
as a synchronization reference, a Tone-Clock circuit p ack provides the system
timing source. The system does not revert to the p rimary if the current reference
is the secondary and is failing; however the system switche s from the local
oscillator to another reference when the new referenc e becomes availab le. Both
the primary and secondary references must reside in the PPN.
There are two kinds of Stratum 4 synchronization that are suppo rted: Type I and
Type II. Stratum 4 type I is more stable than Type II and provides some switc hing
capability at the hard ware level. It is important to note that Stratum 4 Type I
operation is not possible when one or both of the DS1 interface circ uit packs
providing the reference s ources is a TN722. Both must be the TN767B (or higher)
or TN464C (or higher).
MO Name (in
Alarm Log)
Alarm
Level Initial Command to Run Full Name of MO
SYNC MAJOR d isplay errors Synchroniz ation Maintenance
SYNC MINOR display errors Synchroniz ation Maintenance
SYNC WARNING test synchronization Synchronization Maintenance