Справочник Пользователя для ADC Telecommunications Inc. DVLRCS800
ADCP-75-124 • 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.