5-2
Cisco ONS 15501 User Guide
78-14134-02, Release 2.0
Chapter5 Troubleshooting
Isolating the Problem
To verify the Ethernet connection, follow these steps:
Step 1 Make sure that the RJ-45 c onnector is in good workin g condition; then plug it in to the LAN port.
Step 2 Check for LED activity on the LAN port. The left LED is green when a n Ethernet connection is
established. The right LED flickers yellow when a signal is being transmitted to the Ethernet.
Step 3 Check the following areas for p ossible problems if no LEDs ar e on:
•Verify that the RJ-45 connection to t he chassis is firmly made.
•Verify that the RJ-45 connector is in good working condition.
•Verify that the external Ethernet source is on and delivering a signal.
To verify the alarm connection, connect an ohmmet er to the Alarm Out port, through an R J-45 connector.
If the ohmmeter shows a reading of any kind, a connection is present. A very high resistance reading
indicates that there are no alarm conditions; a low r esistance reading indicates that alarm conditions do
exist. See AppendixC, “Connector Pinouts.”
Isolating the Problem
The key to troubleshooting the CiscoONS 15501 is to isolate the problem to a specific component.
When troubleshooting, consider the following components of the CiscoONS 15501:
•Power supply — Includes the power input wiring and associated switches and fuses.
•Cooling system — Includes the fan, which should go on when power is supplied. The air intake vents
and exhaust vents must have adequate ventilati on.
•Front panel indicators — Includes the LEDs on the front panel, wh ich help to identify a fail ure.
•Connecting cables — Includes all of the interface cables that connect the equipment to any
transmission circuit or external device.

Reading the Front Panel LEDs

The front panel LEDs provide the activity or alarm status of the int erfaces or internal circuitry to which
they correspond. If an LED is co nnected to an active circuit and registers a n alarm condition or is not
on, a problem may exist. Table 5-1 lists the front panel LEDs and what the conditions indicate.
Table 5 -1 shows the CiscoONS 15501 front panel.
Table5-1 Cisco ONS 15501 Front Panel LEDs
LED Status Description
Power Green Power is on.
Fail Red Component failure.
LOS1
1. Loss of Signal
Yellow No signal is detected.