Nortel Networks Circuit Card 311 - Manual (Page 895)

Architecture 895
ATTENTION
IMPORTANT!
Each Media Gateway that has a digital trunk must have a clock controller clocked
to an external reference clock.
Note: Clocking slips can occur between systems that are clocked from
different Central Offices (COs), if the COs are not synchronized. The
slips can degrade voice quality.
The recovered clock from the external digital facility is provided to the clock
controller through the backplane-to-clock controller interface. Depending
upon the state of the clock controller (switched on or off), the clock controller
interface in conjunction with software enables or disables the appropriate
reference clock source.
The clock-controller circuitry on NTAK10 is identical to that of the NTAK20.
Note that while several DTI/PRI packs may exist in one system, only one
clock controller may be activated (all other DTI/PRI clock controllers must
be switched off).
ATTENTION
IMPORTANT!
Each Media Gateway that has a digital trunk must have a clock controller clocked
to an external reference clock.
Note: Clocking slips can occur between systems that are clocked from
different COs, if the COs are not synchronized. The slips can degrade
voice quality.
The recovered clock from the external digital facility is provided to the clock
controller through the backplane-to-clock controller interface. Depending
upon the state of the clock controller (switched on or off), the clock controller
interface, in conjunction with software, enables or disables the appropriate
reference clock source.
The clock-controller circuitry on NTAK10 is identical to that of the NTAK20.
While several DTI/PRI packs can exist in one system, only one clock
controller can be activated. All other DTI/PRI clock controllers must be
switched off.
Clocking modes
The clock controller can operate in one of two modes: tracking or
non-tracking (also known as free-run).
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
.