Ds1 Input Module Alarm Modes - Symmetricom SSU-2000e User Manual

Chapter 7 Input Module Reference Data
1-Port and 3-Port DS1 Input Modules
Synchronization Status Messages
The Input module reads and processes Synchronization Status Messages (in
accordance with specifications ANSI T1.403 for DS1 signals), to determine the
traceability of inputs. This traceability information is then used by the Clock modules
in selecting a reference signal and embedded into the system's outputs.
For a DS1 input signal, an SSM is considered valid only after seven of the last ten
received SSMs match. For DS1 signals, the Input module logs an alarm (user-set
level) if 10 seconds elapse and no SSM is detected.
SSM Selection Criteria
If the Input module is configured for provisioned mode, it will use the provisioned
SSM. If configured for automatic mode, the Input module uses the most recent valid
SSM. If a valid SSM is not received, the module uses the provisioned SSM. Refer to
Changing Factory

DS1 Input Module Alarm Modes

The Input module responds to various alarm conditions according to user-set alarm
levels. Each level is associated with a set of actions (or non-actions) as shown in
Table 7-5.
Table 7-5. DS1 Input Module Alarm Modes
Alarm Mode
IGNORE Do nothing
REPORT Generate event message
MINOR Generate event message
MAJOR Generate event message
CRITICAL Generate event message
Fault Port
Alarms Caused by Hardware Problems
The following alarms are generated due to hardware problems:
External Clock Signal PLL Unlocked
– Report event message and perform any other actions as required by the
user-set severity level
– Fault channel, even if severity is less than MAJOR
– Monitor PLL for recovery
176 SSU-2000e User's Guide
Defaults, on page 113, for more information on SSM settings.
Action
Cannot be elevated to a higher severity level
Cannot be elevated to a higher severity level
Elevate to MAJOR if the alarm condition persists
beyond the user-settable elevation time limit
Elevate to Critical if the alarm condition persists
beyond the user-settable elevation time limit
Cannot be elevated as there is no higher severity
level
Alarm Elevation
12713140-002-2 Revision E – October 2006