
Troubleshooting
150-231-184-05, Revision 05
40
October 25, 1999
HLU-231 List 8D
T
ROUBLESHOOTING
This section provides information about system alarms and loopback testing. In addition to these troubleshooting
aids, the Maintenance Terminal provisioning interface includes troubleshooting screens (see
Troubleshooting Screen” on page 36
) that provide a basic graphical analysis of system problems.
S
YSTEM
A
LARMS
lists possible HLU-231 List 8D alarm states and the corresponding front panel messages. More than one
alarm condition can exist at any given time, but only one message can be displayed. In this case only the highest
priority alarm is displayed.
Table 12.
HDSL System Alarms
Front Panel
Message
Alarm State
Description
To Inhibit:
ALRM LOSW
Loss of Sync Word
(a)
(a) When both HDSL loops lose sync word (LOSW), a system alarm condition exists. However, since the HLU-231 enters a
self-test cycling mode, the front panel LED lights yellow instead of red and the
SELF TEST
message displays instead of the
ALRM
message.
One of the HDSL loops has lost
synchronization.
Cannot be inhibited.
ALRM LLOS
Local Loss of Signal
Loss of the DSX-1 input signal.
Cannot be inhibited.
ALRM RLOS
Remote Loss of
Signal
Loss of the HRU DS1 input signal.
Disable the RDA (Remote DS1 Alarm) option. This
prevents an LOS condition at the DS1 input to an
HRU from closing the alarm contacts (pins 20 and
21 on the card-edge connector). The front panel
Status LED still flashes red and the ALRM RLOS
message displays to alert you of the LOS state. LOS
is sent towards the network from the HLU. This
option prevents the common occurrences of a CPE
LOS condition from generating recurring alarms
and AIS payloads.
ALRM
R(L)AIS
(b)
(b) This message is reported in the Span Status screens, but not on the front panel display.
Remote (or Local)
Alarm Indicating
Signal
Indicates an AIS pattern of all ones is
being transmitted (XMT) from the
remote (or local) T1 output port.
Set LBPK option to ENA or DIS.
ALRM MAL1
or
ALRM MAL2
Margin Alarm Loop1
or
Margin Alarm Loop2
The margin on HDSL Loop 1 or
Loop 2 has dropped below the
minimum threshold value set by the
terminal MARGIN ALARM THRES.
Set the Margin Alarm Threshold option to 0 (zero).
ALRM BER
Bit Error Rate
exceeded
The combined T1 and HDSL BER has
exceeded the set threshold limits of
10
-6
or 10
- 7
.
Select NONE for the BER system option.
NONE
No alarm
No current alarm condition.
Cannot be inhibited.