This attribute displays whether an Unusable Transmit Clock
Reference (UTCR) alarm state has been entered. A UTCR alarm
state is entered when a Sonet/Sdh port provisioned to act as a
transmit clock reference has received the code 'do not use for
synchronization' in the S1 byte (in the SONET/ SDH line
overhead) for 2.5 +/- 0.5 seconds.
The condition is cleared after not detecting the 'do not use for
synchronization' code for a period of 10 +/- 0.5 seconds or when
the port is no longer provisioned to act as a transmit clock
reference.
A port is acting as a transmit clock reference if it is provisioned
with a) a clockingSource of line, or b) it has been provisioned as a
primaryReference, secondaryReference or tertiaryReference in the
NetworkSynchronization component.
The unusableTxClockRefAlarm attribute is always set to off when
the component has been locked and left offline.