Nortel NT1R20 Description page 190

Page 166 of 290
553-3001-105 Standard 5.00 June 1999
NT5D33 and NTRB34 Line-side E1 Interface Cards
Alarms
The MMI may be used to activate alarms for the following E1-link
conditions: excessive bit-error rate, frame-slip errors, out-of-frame,
loss-of-signal, and blue alarm. Pre-set thresholds and error durations trip LEI
alarm notifications. For descriptions of each of these E1-link alarm
conditions, see "Performance counters and reporting" on page 184. For
instructions on how to set alarm parameters, see "Set Alarm" on page 171.
For information on accessing alarm reporting, see "Display Alarms" on
page 182, "Display Status" on page 183 and "Display Performance" on
page 185.
Two levels of alarm severity exist for bit errors. Different threshold and
duration settings must be established for each level. When the first level of
severity is reached (alarm level 1), the MMI will cause the external alarm
hardware to activate, the RED ALARM LED on the faceplate will be lit, an
alarm message will be displayed on the MMI terminal, and an entry will be
created in the alarm log and printed to the MMI port. When the second level
of severity is reached (alarm level 2), the MMI will perform all functions
performed at alarm level 1, and, in addition, the LEI will enter
line-conditioning mode. In this mode, the LEI will send either "on-hook" or
"off-hook" signals for all 30 ports to the Meridian 1, depending on how the
dip switch for line processing is set (dip switch 2, position 6). See Table 38
on page 150.
If the MMI detects E1-link failures for any of the other conditions monitored
(out-of-frame, excess frame slips, loss-of-signal, and blue alarm condition),
the LEI automatically performs all alarm level 2 functions. The MMI also
sends a yellow alarm to the distant end LTU. Alarms may be set to self-clear
when the alarm condition is no longer detected. See "Set Clearing" on
page 175.
All alarms activated produce a record in the alarm log. The alarm log
maintains records for the most recent 100 alarms, and can be displayed,
printed, and cleared. The alarm log displays or prints the alarms in descending
chronological order, beginning with the most recent alarm. Notifications in
the alarm log include the date and time of the alarm's occurrence.