Total Access 362R Single Family Unit with RF Return Installation and Maintenance Guide
46
61187715G1-5B
Downstream Signal Level Verification
A
valid
optical
power
level
delivered
by
the
OLT
must
be
received
at
the
drop
cable
point
in
the
GPON
to
assure
proper
ONT
ranging
and
operation.
There
are
two
optical
wavelengths
to
consider
in
the
downstream
direction
that
will
contribute
to
the
absolute
optical
power
level
delivered
to
the
ONT:
1490
nm
and
1550
nm
wavelengths.
The
1490
nm
wavelength
is
used
for
digital
data.
The
1550
nm
wavelength
is
used
for
the
video
overlay.
The
individual
optical
power
levels
that
should
be
present
at
the
optical
fiber
that
is
connected
to
the
ONT
are
listed
in
To
verify
the
correct
downstream
optical
signal
levels
are
present:
1. Ensure
all
connectors
are
clean
and
dry.
Refer
to
for
details.
2. Setup
and
calibrate
the
OPM
or
OLTS
for
wavelengths
that
apply
to
FTT
transmissions
(that
is
1310,
1490,
1550,
and
1610
nm).
Verify
the
test
equipment
is
capable
and
setup
for
wavelength
filtering
so
that
you
do
not
obtain
an
undesired
reading
of
the
absolute
optical
power
from
all
contributing
wavelengths.
Instead
you
are
trying
to
measure
the
individual
wavelength
optical
power
levels.
3. Connect
optical
fiber
drop
cable
to
the
test
equipment
as
shown
in
.
Figure 26. Downstream Test Configuration
4. Verify
the
test
equipment
measurement
results
are
within
the
optical
signal
level
ranges
described
in
above.
5. Do
one
of
the
following:
• If
the
results
are
not
within
range,
complete
the
necessary
testing
and
verification
steps
to
validate
points
further
up
the
network,
towards
the
OLT,
to
locate
the
cause
of
the
optical
signal
level
differences.
• If
the
measurement
results
are
within
range,
perform
the
steps
in
Table 9. Downstream Power Levels
Optical Wavelength
Minimum Power Level
1490
nm
(digital)
–28
dBm
1550
nm
(video)
–8
dBm
1490 nm
Drop cable
OPM
OLTS
or
1550 nm
