Verilink DCSU 2911 (880-502647-001) Product Manual - Manual (Page 71)

Troubleshooting
Verilink DCSU 2911 User Manual 5-5
Loss of Frame
Alignment
(E1 Only)
This condition occurs when three consecutive in-error frame alignment
signals (words) are received, or when Bit 2 in a frame containing the non-
frame alignment signal (NFAS word) is received in error three consecutive
times.
The condition clears when the following events are satisfied:
• The frame alignment signal is detected in frame N.
• The non-frame alignment signal 1 is detected in frame N+1.
• The frame alignment signal is detected in frame N+2.
Loss-of-frame alignment (LOFA) after one continuous second causes a
major alarm and activates the relay contacts on the rear connector panel
of the CIM.
This alarm activates the CFA if the LOFA is active from 2 to 45 seconds (as
defined by the user).
Frame
Alignment
Signal Error
Rate (FASER)
(E1 Only)
This alarm indicates that the FAS error rate exceeds a user-selectable
threshold of 10 -3 or 10 -6 for at least four seconds. This user-selectable
alarm can be designated as a major or minor alarm and activates the relay
contacts on the rear connector panel of the CIM.
This alarm activates the CFA if the FASER is active from 12 to 60 seconds
(as defined by the user).
Loss of TS16
Multiframe
Alignment
(LOMA)
(E1 Only)
This condition occurs when the module cannot find the multiframe
alignment signal (MAS) pattern on TS16 when enabled for CAS signaling.
This alarm activates the CFA if the LOMA is active from 2 to 45 seconds
(as defined by the user).
Minor Alarms Minor alarm fault conditions do not affect traffic along the network line.
They generate a minor alarm.
Alarm Type Description
Power Supply
Missing
In redundant power supply configurations, this alarm indicates that one of
the redundant power supplies has failed or has been removed from the
shelf.
Remote
Alarm
Indication
(RAI)
RAI. This alarm indicates that the remote end is in a state of alarm. A
Remote Alarm or Remote Alarm Indication is the alarm a receiving channel
bank or multiplexer sends to the other end of the circuit when it detects a
Loss Of Signal or Loss Of Frame. There is a 2- to 3-second integration
period upon detection of LOS or LOF before a Yellow Alarm is sent to the
far-end equipment. This condition is also referred to as a Yellow Alarm.
Bipolar
Violation
(BPV)
Threshold
A violation of the T1 bipolar AMI transmission pattern requiring
successive Ones (pulses) to be transmitted as pulses of opposite
polarities. A BPV alarm indicates transmission errors. However, B8ZS
patterns contain intentional BPVs that are not counted as errors.
Severely
Errored
Second (SES)
15 min. Threshold/SES 24 hr. Threshold—An SES alarm is declared when
320 or more ESF error events occur within one second, or when an OOF
(Out-Of-Frame Second) occurs. An SES is a one-second period containing
greater than 30% errored blocks (more than 1 errored bit) or at least one
Severely Disturbed Period (SDP).
Bit Error Rate
(BER)
Threshold
The Bit Error Rate is the ratio of the number of bit errors received to the
total number of bits transmitted in a given interval. The BER threshold
indicates the level above which a CSU alarm is generated and reported.
Alarm Classification/
Alarm Type Description