DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Object Repair Procedures
9-1562SYNC (Synchronization)
9
SYNC (Synchronization)
This section discusses sync hronization problems local to t he switch. For further
information about synchronization inc luding network synchronizat ion, see the

AT&T Network and Data Connectivity

.
Synchronization Maintenance is comp osed of both hardware and software
components and its p urpose is to provide a c ommon reference frequency for
reliable digital c ommunication between the G3r system and other PBXs, Central
Offices(COs) or Customer-Premises Equipment (CPE). Synchronization is
implemented using se veral system components includ ing:
■TN768 or TN780 Tone-Clock
■TN722, TN767 and TN 464 DS1 Interfaces (all suffixes)
■TN572 Switch Node Clock
■TN573 Switch Node Interface
■TN570 Expansion Interface
Synchronization is achieved betwe en the Processor Port Network (PPN) and the
Expansion Port Networks (EPNs) via the port network connectivity (PNC)
between the networks. Depending on the network synchronization plan and the
status of synchronization sources, the sys tem timing reference may be a
Tone-Clock circuit pack, DS1 interface or UDS1 c ircuit packs, or an external
Stratum 3 clock. Stratum 4 synchronization extracts timing information directly
from a DS1 reference, UDS1 reference, or a Tone-Clock. Stratum 3
synchronization requires the use of a Stratum 3 cloc k that provides a timing
signal derived from DS1 references to the Tone-Clock circ uit 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 and redund ant
components.
If both a primary and a s econdary reference are adm inistered for Stratum 4
synchronization, both references must resid e in the same port network.
MO Name (in
Alarm Log) Alarm Level Initial Command to Run Full Name of MO
SYNC MINOR display errors Synchronization
SYNC WARNING test synchronization Synchronization