ADTRAN TSU 120 User Manual page 116

Appendix B. Understanding TR-08
Table B-1 explains what conditions trigger alarms and how alarms are
processed when received by the TSU 120.
Name
FELP
Loss of Data
OOF
Loss of Signal The TSU 120 will send MINOR ALARM and the A
BPVs
Protection
Line Switch
B-2
Alarm Conditions
Table B-1.
When the TSU 120 receives a FELP alarm, it will loop
the incoming data directly to the outgoing data. LINE
ON is placed in history. The alarms and loopback are
cleared when FELP is no longer received.
The TSU 120 will send MINOR ALARM and the A
SHELF ALARM for 2.5s when it quits receiving the
data link on the T-Span. It will also report TR-08 DL
Down in the history. After 2.5s, MAJOR ALARM, A
SHELF ALARM are sent across the Data Link.
The TSU will send MINOR ALARM and A SHELF
ALARM upon receiving an out-of-frame condition.
TR-08 DL Down and RED ALARM are declared in
history for severe framing errors. After 2.5s, MAJOR
ALARM, A SHELF ALARM are sent across the Data
Link.
SHELF ALARM for 2.5s when it quits receiving a
signal from the far end. It will also report TR-08 DL
Down and LOS in the history. After 2.5s, MAJOR
ALARM, A SHELF ALARM are sent across the Data
Link, and RED ALARM is declared in history.
BPVs that are received at a rate greater than the
threshold set under TR-08 options, will cause
MINOR ALARM and A SHELF ALARM to be sent
on the DL. If the BPVs remain above the threshold for
2.5s, the TSU 120 will send MAJOR ALARM on the
DL. No events are placed in history.
The TSU will not respond to this alarm.
TSU 120 User Manual
Explanation
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