Nortel Circuit Card, Installation Manual, Page: 738 / 908

Page 738 of 906 NTAK20 Clock Controller daughterboard
553-3001-211 Standard 3.00 August 2005
Free-run (non-tracking)
In free-run mode, the clock controller does not synchronize on any outside
source. Instead, it provides its own internal clock to the system. This mode
can be used when the system acts as a master clock source for other systems
in the network. Free-run mode is undesirable if the system is intended to be a
slave to an external network clock. Free-run mode can occur when both the
primary and secondary clock sources are lost due to hardware faults or
invoked using software commands.
Physical description
Faceplate LEDs
Each motherboard has five DTI/PRI LEDs and one clock controller LED. The
clock controller LED is dual-color (red and green). The clock controller LED
states are described in Table 237.
Table 237
Faceplate LEDs
State Definition
On (Red) NTAK20 is equipped and disabled.
On (Green) NTAK20 is equipped, enabled, and is either locked to a
reference or is in free run mode.
Flashing
(Green) NTAK20 is equipped and is attempting to lock (tracking
mode) to a reference. If the LED flashes continuously over
an extended period of time, check the CC STAT in LD 60.
If the CC is tracking this may be an acceptable state.
Check for slips and related clock controller error
conditions. If none exist, then this state is acceptable, and
the flashing is identifying jitter on the reference.
Off NTAK20 is not equipped.