LTPH-SM-1052-04
Managing
Alarms
HMS-358 List 5 and List 6
July 14, 2002
67
L
INE
U
NIT
A
LARMS
The Shelf Status menu reports the alarm status for each line unit. This includes both physical alarms (LOS
ALARM BUS and FUSE ALARM BUS) as well as alarm messages shown in
The LOS ALARM BUS field on the Shelf Status menu indicates when any unmanaged line unit (or any other
non-manageable card installed in the shelf) is reporting a minor alarm on pin H of the line unit edge connector.
Refer to the shelf and line unit user manuals for information on using pin H.
The FUSE ALARM BUS field on the Shelf Status menu indicates when any line unit (or any other card installed
in the shelf) is reporting a fuse alarm on pin 10 of the line unit edge connector. Refer to the shelf and line unit user
manuals for information on pin 10.
The line unit H1ES, H2ES, and DS1 Errored Seconds Threshold alarms are not supported by
the Shelf Status menu. If any of these conditions exist on a line unit, the line unit status
indicates NORMAL. For this reason, use of the line unit Errored Seconds Threshold alarm
option is not recommended. Refer to the line unit documentation for instructions on setting
the Errored Seconds Threshold option.
Table 10.
Line Unit Alarm Messages
Alarm Message
Definition
Description
LOSW
Loss Of Sync Word
Loss of signal on an HDSL span.
RLOS
Remote Loss Of Signal
Loss of DS1 signal at the remote unit.
LLOS
Local Loss Of Signal
Loss of DSX-1 signal at the line unit.
MAL1, MAL2
Margin Alarm 1, Margin Alarm 2
Loop margin has dropped below the user-set,
minimum threshold level.
NORMAL
No alarm condition exists.
UNKNOWN
Line unit failed to respond to status requests.
Enable the ALM (alarm) option of an unmanaged line unit to allow the unit to trigger an alarm
on pin H of the shelf connector (the LOS Alarm Bus). A managed HLU initiates an HMU alarm
message over the digital management bus between the HLU and HMU. An unmanaged HLU or
a T1 repeater triggers the HMU alarm by driving the LOS Alarm Bus to ground. Refer to the line
unit’s documentation for instructions on enabling the ALM option.
