Symmetricom SDU-2000, User Manual

Page: 149 / 470

12713020-002-2 Revision D – April 2004 SSU-2000 User’s Guide 149
Input Module Reference Data
1-Port and 3-Port E1 Input Modules
Once in episode:
Log LOS alarm, taking appropriate action per the assigned severity level
Invalidate current phase measurements
Others (AIS, BPV, CRC, and OOF)
Once in episode, the system takes appropriate action according to the severity level
assigned to the alarm.
LOS Phase Considerations
Phase reading not valid when in episode
Zero phase reading when episode ends
If signal returns before the port goes into episode, normalize subsequent phase
measurements to show continuous phase numbers before and after the loss of
signal.
Others
Phase reading valid
Hierarchy of Alarm Signals
LOS
AIS
OOF
BPV/CRC
The Input module does not report alarms below the level of an active alarm.
Cesium Fault
Facilitates compatibility with older Hewlett Packard units
Only valid if port one is configured to receive an unframed input signal
User can select high or low logic level as alarmed
If the hardware indicates that the cesium fault level matches the alarmed setting,
log an AIS alarm against port 1
Clear the alarm when the hardware’s cesium fault level no longer matches the
alarmed level
Input Measurement Problems
If the MTIE values for a selected clock exceed either of the MTIE masks, the Input
module takes appropriate action according to the severity level associated with the
MTIE alarms.
If a received SSM has a lower PQL than the provisioned value assigned to the port
and the port has SSMs enabled, the Input module performs the action required by
the alarm mode.