Nortel Networks Circuit Card 사용자 설명서

 NTAK20 Clock Controller daughterboard

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.

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.

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.