Revision 01
Section 350-231-164
HLU-231 List 6D
11
Testing
Minor alarm and diagnostic messages routinely appear on the HLU-231
front-panel four-character display. This display automatically turns on when
power is initially applied to the HLU-231. To conserve power, the display
remains on for only five minutes if neither the MODE or SEL buttons are
pressed. The use of either button activates the four-character display and
restarts the 5-minute power-control timer.
Alarms
Only one alarm can be displayed at a time, so the highest priority alarm is dis-
played if more than one alarm exists. The following table lists the alarms
ordered by priority:
Status Menu Alarm Messages
Message
Full Name
Description
NONE
No Alarms
LLOS
Local Loss of Signal
No signal from HLU-231 local T1 inter-
face.
RLOS
Remote Loss of Signal
No signal from HRU remote T1
interface.
LOSW1 or
LOSW2
Loss of Sync Word 1 or 2 HDSL loop 1 or 2 has lost sync.
H1ES or
H2ES
HDSL Loop 1 or 2
Errored Second
Loop 1 or 2 has incurred a CRC error.
DS1
Digital Service 1
DS1 input BPVs at the HRU have
exceeded the user selected ES thresh-
old.
RAIS
Remote Alarm Indicating
Signal
Indicates an AIS (all “1”) pattern is being
transmitted from the remote or T1 output
port.
MAL1 or
MAL2
Margin Alarm 1 or 2
The margin on HDSL loop 1 or 2 has
dropped below the threshold (1 to 15
dB) set by the user.
CHREV
Channels Reserved
The Loop 1 & 2 HDSL pairs are
reversed at the HRU input port. Loop 1
is specified to carry the (-) simplex DC
voltage, and Loop 2 is specified to carry
the (+) simplex DC voltage.
Summary of Contents for HLU-231
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