Nortel Networks 1000 - Manual (Page 238)

238 NT5D11 and NT5D14 Lineside T1 Interface cards
declared and silence is sent on all receive timeslots. The alarm is cleared
if, after two seconds, neither a loss of signal, out of frame condition, nor
blue alarm condition occurs.
If a repeating device loses signal, it immediately begins sending an
unframed all 1’s signal to the far-end to indicate an alarm condition. This
condition is called a blue alarm, or an Alarm Indication Signal (AIS). If an
AIS is detected for more than two seconds, a level 2 alarm is declared,
and silence is sent on all receive timeslots. The alarm is cleared if, after
two seconds, neither a loss of signal, out of frame condition, nor blue
alarm condition occurs.
Alarm Disable
The Alarm Disable (A D) command disables the external alarm contacts.
When this command is typed, the MMI displays the message "Alarms
Disabled" and the MAINT LED turns on. In this mode, no yellow alarms
are sent and the Lineside T1 card does not enter line processing mode.
Alarm messages are still sent to the MMI terminal and the LED light
continues to indicate alarm conditions.
Alarm Enable
The Alarm Enable (A E) command set does the opposite of the Alarm
Disable command set. It enables the external alarm contacts. When this
command set is typed in, the MMI displays the message "Alarms Enabled."
In this mode, yellow alarms can be sent and the Lineside T1 card can
enter line processing mode.
Clear Alarm
The Clear Alarm (C A) command set clears all activity initiated by an
alarm: the external alarm hardware is deactivated (the contact normally
open is reopened), the LED light goes out, an entry is made in the alarm
log of the date and time when the alarm is cleared, and line processing
ceases (for alarm level 2 only). When this command set is typed in, the
MMIl displays the message "Alarm acknowledged." If the alarm condition
still exists, the alarm is declared again.
Display Alarms
A detailed report of the most recent 100 alarms with time and date stamps
can be displayed by entering the Display Alarms (D A) command set into
the MMI. Entering the Display Alarms (D A) command set causes a screen
similar to the following to appear:
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.