Lucent Technologies DDM-2000 OC-3, User & Service Manual

Page: 2073 / 2536

DLP-503
: Detailed Level Procedure 363-206-285
Page 1 of 10 Issue 2, February 2000
DDM-2000 OC-3 M
ULTIPLEXER
Install TGS/TG3 Circuit Packs
1.
!
CAUTION:
The timing mode of all nodes should be checked before a node is placed
in service. Improper timing modes may cause the system to act
unpredictably or cause a service interruption (for example, if all nodes are
set to line timed mode).
NOTE:
The timing mode may be provisioned as Free Running, DS1 External, or
Line Timed. In free-running mode, the TGS/TG3 gets timing from an
oscillator on the TGS/TG3. In DS1 external timing mode, the TGS/TG3
gets timing from an external DS1 reference input. In line-timed mode, the
TGS/TG3 gets timing from a reference clock recovered from a received
OC-3 line rate signal. In TARP Release 13 or later, free-running timing is
the factory default. In TARP Release 13 or later, when a BBF2B/BBF2C
TGS or BBF4 TG3 is installed, either the MAIN OLIUs or FUNCTION
UNITS C OLIUs can be selected as the synchronization source using the
command
set-sync:src={main,fn-c};
.
NOTE:
In addition to the same options as the BBF2 TGS, the BBF2B/BBF2C
TGS or BBF4 TG3 may be provisioned to provide a DS1 output for
intershelf timing distribution (mult mode) or for network timing distribution
(sync mode). When in
sync out mode, the DS1 output signal derives its
timing from the incoming OC-3 line signal from the MAIN OLIUs or
optionally from the FUNCTION UNITS C OLIUs using the
set-sync:src={main,fn-c};
command.
NOTE:
Tables A and B depict all the possible timing topologies for the BBF2
TGS and BBF2B/BBF2C TGS or BBF4 TG3 circuit packs which can be
encountered on adjacent network elements (NE) with some comments or
cautionary notes on their application. When the NE is provisioned for line
timing or with the DS1 output in SYNC OUT mode, the assumption is that
the NE is deriving its timing from the optical interface shared between the
two NE’s.