User Manual

ADCP-75-126 • Issue B • April 2002 • Section 5: Maintenance
Page 5-12
© 2002, ADC Telecommunications, Inc.
7. Verify that the power loss is within specifications. The optical loss budget for 9/125,
single-mode fiber is 25 dB (for BER of 10
-6
). The optical power level should not exceed –
15 dBm to avoid overdriving the optical receiver. If the power loss is not within
specifications, repair or replace the optical fiber and/or connector per local practice.
8. Repeat steps 3 through 6 for each optical fiber that requires testing.
9. Reconnect the optical fibers at the HU and the STM.
10. When ready to put the system back into service, place the On/Off switch in the ON
position (press I) at both the HU and STM.
11. Notify the NOC or alarm monitoring service that the system is going back online.
4.2 Optical Loopback Test
A faulty optical port, a break in an optical fiber, or a fault in an optical connector will interrupt
communications between fiber linked components. The following procedures provide tests to
determine if a fault exists with the primary optical ports (PORT 1/PORT 2) or with the
secondary optical port (PORT 3).
4.2.1 PORT 1/PORT 2 Loopback Test
1. Put on the IR filtering safety glasses.
2. Notify the NOC or alarm monitoring system operator that the system is going offline.
3. At the HU or STM (whichever unit is being tested), place the On/Off switch in the OFF
position (press O).
4. Disconnect the optical fiber connectors from the PORT 1 and PORT 2 optical ports and
place a dust cap over each connector.
5. Plug a 15 dB in-line optical attenuator into the PORT 1 optical port.
6. Connect a patch cord between the optical attenuator and the PORT 2 optical port.
7. Place the On/Off switch in the ON position (press I) and observe the PORT 1/PORT 2
LED indicator.
8. The PORT 1/PORT 2 LED indicator will turn either red or green. If the LED turns red, the
primary optical transmitter or receiver is faulty. Replace the unit and then recheck system
operation. If the LED turns green, the optical ports are good.
9. Place the On/Off switch in the OFF position (press O).
10. Remove the optical attenuator from the PORT 1 optical port.
Danger: This equipment uses a Class 1 Laser according to FDA/CDRH rules. Laser radiation
can seriously damage the retina of the eye. Do not look into the ends of any optical fiber. Do not
look directly into the optical transmitter of any unit or exposure to laser radiation may result.
An optical power meter should be used to verify active fibers. A protective cap or hood MUST
be immediately placed over any radiating transmitter or optical fiber connector to avoid the
potential of dangerous amounts of radiation exposure. This practice also prevents dirt particles
from entering the connector.