User Manual
ADCP-75-150 • Preliminary Issue A • March 2003 • Section 5: Maintenance
Page 5-11
©
2003,
ADC
Telecommunications,
Inc.
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.
Ve ri f y
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
10. At
the
far
end
HU
or
STM,
place
the
On/Off
switch
in
the
OFF
position
(press
O).
11. Disconnect
the
optical
power
meter
from
the
near
end
of
the
optical
fiber.
12. Connect
the
optical
power
meter
to
the
far
end
HU
(Port
1)
or
STM
(Port
2).
13. At
the
far
end
HU
or
STM,
place
the
On/Off
switch
in
the
ON
position
(press
I).
14. Measure
the
optical
output
power
of
the
far
end
HU
or
STM.
The
power
level
of
the
optical
output
signal
from
the
HU
or
STM
must
meet
the
following
specification:
HU
Forward
Path
Output
Signal
(Port
1):
0
+
1
dBm
STM
Reverse
Path
Output
Signal
(Ports
2
and
3):
+2
+
1
dBm
If
the
power
level
of
the
optical
output
signal
is
within
specifications,
the
optical
fiber
is
faulty.
If
the
power
level
of
the
optical
signal
is
not
within
specifications,
the
far
end
HU
or
STM
optical
transmitter
is
faulty.
15. At
the
far
end
HU
or
STM,
place
the
On/Off
switch
in
the
OFF
position
(press
O).
16. Disconnect
the
optical
power
meter
from
the
far
end
HU
or
STM.
17. Reconnect
the
optical
fibers
at
the
HU
and
the
STM.
Note:
Turning
off
the
HU
and
STM
disables
the
respective
lasers
which
is
necessary
in
order
to
safely
inspect
and
clean
the
optical
connectors.