User Manual

ADCP-75-158 • Preliminary Issue A • June 2003 • Section 5: Maintenance
Page 5-11
© 2003, ADC Telecommunications, Inc.
4 TEST PROCEDURES
This section provides procedures for common troubleshooting and maintenance tests. Refer to
these procedures as needed when specified in the Fault Isolation and Troubleshooting tables in
Section 3.
4.1 Optical Power Test
A break in an optical fiber or a fault with the optical connector will interrupt communications
between linked components or generate excessive errors. Use the following procedure to isolate
a problem with an optical fiber or connector.
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 and at the STM, place the On/Off switches in the OFF position (press O).
4. Disconnect the optical fiber connectors for the fiber to be tested at the HU and the STM.
5. Inspect the optical connectors. Verify that connectors are clean and that no scratches or
imperfections are visible on the fiber end. Clean and polish the optical connectors if necessary.
6. Connect the optical power meter to the output (receiver) end of the optical fiber. If an
attenuator was included in the fiber link, make sure the attenuator is installed.
7. Connect the input (transmitter) end of the optical fiber to the far end HU or STM.
8. At the far end HU or STM, place the On/Off switch in the ON position (press I).
9. Using the far end HU or STM as an optical light source, measure the optical power at the
near end of the optical fiber. The power level of the optical input signal at the HU or STM
must fall within the following ranges:
STM Forward Path Input Signal (Port 1): –15 to –25 dBm (with attenuator installed)
HU Reverse Path Input Signal (Port 2): –15 to –23 dBm (with attenuator installed)
If the power level of the received optical signal is within the specified range, the optical
fiber and the far end unit are good. If the power level of the received signal is not with
the specified range, either the optical fiber is faulty or the far end unit optical transmitter
is faulty. Continue with test procedure to isolate the problem
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.
Note: Turning off the HU and STM disables the respective lasers which is necessary in
order to safely inspect and clean the optical connectors.