Severity Levels

Not Alarmed (NA)

AID Type

Shelf

Subshelf

Date

Month/day/year that the condition was detected

Time

Hour:minute:second that the condition was detected

Probable Cause

HOLDOVRSYNC (Holdover synchronization mode)

Effect on Service

Standing Condition (SC)

Alarm Entity Type

COM

Description

holdover mode active

Likely Cause

The system was manually switched to holdover mode (by selecting Fault → Timing/Sync Protection Switch → Clock Mode Switch) and the switch has not been reset. The system is provisioned for sync message signaling, but the upstream system from which it line-times has not been provisioned for sync message signaling.

The system automatically switched to holdover mode due to failure of the timing references and:

• The reference failures have not cleared.

• The system is provisioned for nonrevertive synchronization mode.

• The system is provisioned for External timing and no external timing references are available.

• The system is turned-up with default conditions and no incoming external timing input signal is present.

• The system is provisioned for line-timed operation and the optical line or OLIU circuit pack has failed, or a message indicating an upstream clock problem has been received on the sync message bits of the optical line.

Visible Indication

None

Action

Proceed to Procedure 5-45: Clear "holdover" conditions/alarms.