Symmetricom SDU-2000, User Manual

Page: 158 / 470

Input Module Reference Data
1-Port and 3-Port DS1 Input Modules
158 SSU-2000 User’s Guide 12713020-002-2 Revision D – April 2004
Others (AIS, BPV, CRC, and OOF)
Once in episode, take 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 Signal Faults
The following alarms are listed in the order of most to least severe:
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. Refer to the
ALARM command in Interactive
Command Set , on page 315, for more information on alarm settings.
DS1 Input Module Events Reported
The 3-Port DS1 Input module reports the event types listed in Table 7-6 when they
occur. See Event Messages , on page 254, for more information on events.