User Manual
ADCP-75-110 • Issue 2B • July 2001
Page 50
©
2001,
ADC
Telecommunications,
Inc.
5.4 Test Procedures
5.4.1 Optical Loopback Test Procedure
A
faulty
optical
port,
a
break
in
an
optical
fiber,
or
a
fault
in
an
optical
connector
will
interrupt
communications
between
fiber
linked
components.
Use
the
following
procedure
to
determine
if
a
fault
exists
with
an
optical
port
or
with
an
optical
link:
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
transceiver
of
any
digital
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
transceiver
or
optical
fiber
connector
to
avoid
the
potential
of
dangerous
amounts
of
radiation
exposure.
This
practice
also
prevents
dirt
particles
from
entering
the
transceiver
or
connector.
1.
Put
on
the
IR
filtering
safety
glasses.
2.
At
the
DHU
or
supporting
DEU,
place
the
PORT
ON/OFF
switch
for
the
fiber
port
or
link
to
be
tested
in
the
OFF
position
(press
O).
3.
Disconnect
the
optical
connectors
at
the
DHU
or
supporting
DEU
optical
port
(near
end
of
fiber)
and
place
a
dust
cap
over
each
connector.
4.
Plug
a
loopback
into
the
optical
port
to
be
tested
as
shown
in
Figure
24.
16767-A
OPTICAL LOOPBACK
CONNECTION DETAIL
PORT 1
OPTICAL
TRANSCEIVER
OPTICAL
LOOPBACK
Figure 24. DHU/DEU Loopback Test
5.
At
the
DHU
or
supporting
DEU,
place
the
PORT
ON/OFF
switch
in
the
ON
position
(press
I).
6.
The
PORT
OK/NOK
LED
will
turn
either
red
or
green.
If
the
LED
turns
red,
the
optical
port
is
faulty.
Replace
the
DHU
or
DEU
and
then
recheck
system
operation.
If
the
LED
turns
green,
the
optical
port
is
good.
Proceed
to
step
7
to
continue
the
test
procedure.