Nortel Circuit Card 311 Reference page 950

950 NTAK79 2.0 Mb PRI card
that it is within specifications. On failure (both out of specification), the
clock controller enters the HOLDOVER mode and continuously monitors
both references. An automatic switchover is initiated to the reference that
recovers first. If the secondary recovers first, then the clock controller
tracks to the secondary, but switches over to the primary when the primary
recovers. If the primary recovers first, the clock controller tracks to the
primary.
If the software command "track to secondary" is given, the clock controller
tracks to the secondary reference and continuously monitors the quality
of both primary and secondary references. If the secondary becomes
out of specification, the clock controller automatically tracks to primary
provided that it is within specifications. On failure (both out of spec.), the
clock controller enters the HOLDOVER mode and continuously monitors
both references. An automatic switchover is initiated to the reference that
recovers first. If the primary recovers first, then the clock controller tracks to
the primary, but switches over to the secondary whenever the secondary
recovers. If the secondary recovers first, then the clock controller tracks
to the secondary.
A time-out mechanism prevents chatter due to repeated automatic switching
between primary and secondary reference sources.
If the software command "track to primary" is given, the clock controller
tracks to the primary reference and continuously monitors the quality of
both primary and secondary references. If the primary becomes out of
specification, the clock controller automatically tracks to secondary provided
that it is within specifications. On failure (both out of specification), the
clock controller enters the HOLDOVER mode and continuously monitors
both references. An automatic switchover is initiated to the reference that
recovers first. If the secondary recovers first, then the clock controller
tracks to the secondary, but switches over to the primary when the primary
recovers. If the primary recovers first, the clock controller tracks to the
primary.
If the software command "track to secondary" is given, the clock controller
tracks to the secondary reference and continuously monitors the quality
of both primary and secondary references. If the secondary becomes
out of specification, the clock controller automatically tracks to primary
provided that it is within specifications. On failure (both out of spec.), the
clock controller enters the HOLDOVER mode and continuously monitors
both references. An automatic switchover is initiated to the reference that
recovers first. If the primary recovers first, then the clock controller tracks to
the primary, but switches over to the secondary whenever the secondary
recovers. If the secondary recovers first, then the clock controller tracks
to the secondary.
Copyright © 2003-2008, Nortel Networks
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Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008