Nortel Networks 1000 - Manual (Page 793)

Architecture 793
loopback. Clock recovery circuitry within the receiving device extracts the
2.0 MHz clock. This clock is used to generate the frame and multiframe
count and is sent to the clock controller as a reference.
The AMI data of the carrier is converted to digital and fed to the input
selector as well as the output selector for far end loopback. Clock recovery
circuitry within the receiving device extracts the 2.0 MHz clock. This clock
generates the frame and multiframe count and sends them to the clock
controller as a
Clock controller interface
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.
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).
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
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