Instruction Manual

Fault finding and clearing
DN00283717 © Nokia Corporation 25 (26)
Issue 2 DRAFT 1 - en Nokia Proprietary and Confidential
Figure 4. Fault finding flow chart
Alarm ON
Local Unit
Alarm?
Is it a
downlink or
uplink alarm?
YES NO
ULDL
The Local Unit
is faulty
YES NO
Remote Unit
Alarm?
The laser is faulty
or under stress
Is there an
input signal?
Connect an input
signal to the RU
YES NO
The fault is
in the fibre optic cable
Are the optical
connectors clean?
The fibre optic cable is either broken
or the splices are not perfect.
OTDR action is required
Clean the optical
connectors
YES NO