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Page 4 of 6
Troubleshooting (Problem Receipt,
Diagnosis & Resolution
a.
Obtain the following information regarding the equipment and the trouble:
b.
Alarms: During a trouble condition, the DDM-2000 displays alarms that help in
troubleshooting. The USER PANEL and circuit pack LEDs indicate the alarms;
alarms can also be remotely monitored on a PC via a modem. The types of alarms
are:
c.
Given the high reliability of the DDM-2000 Multiplexer, it is likely (~ 80% probability)
that the trouble lies outside of the DDM-2000. It could be located in the upstream or
downstream devices in the network, and in the quality of data being received by the
DDM-2000. This possibility should be kept in mind during the troubleshooting
process.
d.
Check for the following symptoms to form a preliminary diagnosis (this can be done
over the phone with the user, if you are off site):
Table 2.
Troubleshooting Symptoms
Symptom
USER PANEL PWR ON
LED OFF
USER PANEL CR, MJ, or
MN LED ON
Circuit pack FAULT LED
ON
Circuit pack FAULT LED
FLASHING
Nature of observed problem, name, and telephone number of on-site
customer contact, circuit pack identifications for the DDM-2000 OC-3/OC-12
Multiplexer
Dial-in phone number for the DDM-2000, Login ID and password. Note:
Information on access to the customer's DDM-2000 system is sensitive and
should be treated accordingly; only qualified persons who have a clear need
to know should request and/or accept such information.
Network map or diagram showing all equipment connected to the DDM-2000
inputs and outputs, and preferably the network of interest showing cross-
connection report.
Critical Alarm: Loss of service to more than 96 DS0 channels (4 DS1).
Major Alarm: Loss of service to 96 or less DS0 channels.
Minor Alarms.
Cause
Loss of Power
Critical, Major, or Minor
Alarm
Circuit pack failure
Signal bad (LOS, LOF,
BER, or LOP); failure of
other equipment; failure of
fiber or cable
DDM-2000 OC-3 M
Issue 3, June 2001
Action
Restore Power
Log on to network and
continue diagnosis
Reseat circuit pack. If fault
remains, replace circuit
pack
Trouble likely to be
external to DDM-2000.
Log on to network and
continue diagnosis
ULTIPLEXER
363-206-285
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