User Manual
ADCP-75-136 • Issue 1 • November 2002
Page 19
©
2002,
ADC
Telecommunications,
Inc.
If
back-up
powering
is
required,
it
is
recommended
that
the
building
Uninterruptible
Power
Supply
(UPS)
system
be
used
to
provide
back-up
power
to
the
DHU
and
DEU
in
the
event
of
an
AC
power
outage.
This
will
also
power
all
the
DRU’s
that
are
powered
by
the
DHU
or
DEU.
3.3.2 DRU Powering
The
DRU
is
powered
by
48
Vdc
power
which
is
input
to
the
DRU
through
the
front
panel
RJ-
45
connector.
Power
to
the
DRU
may
be
provided
by
the
DHU,
DEU,
or
by
a
120
Vac
to
48
Vdc
power
converter
(available
separately
as
an
accessory
item)
plugged
into
a
properly
grounded
120
Vac
outlet.
The
DRU
has
a
current
rating
of
400
mA
at
48
Vdc
input.
If
the
DRU
will
be
powered
by
the
DHU
or
DEU,
the
power
cable
must
be
fabricated
on-site
by
the
installer.
Category
3
or
5
twisted
pair
cable
should
be
used
for
the
power
supply
cable.
The
maximum
recommended
length
of
the
power
cable
is
500
meters.
The
power
cable
must
be
routed
between
the
DHU
or
DEU
and
the
DRU.
Both
ends
of
the
power
cable
must
be
terminated
with
a
male
RJ-45
connector.
If
the
DRU
will
be
located
more
than
500
meters
from
the
DHU
or
DRU,
it
must
be
locally
powered
by
a
48
Vdc
power
converter.
The
DRU
may
be
powered
locally
by
the
ac/dc
converter,
shown
in
Figure
10,
which
is
available
as
an
accessory
item.
The
converter
is
a
UL
Listed
stand
alone
Limited
Power
Supply
(LPS)
unit
with
a
rated
output
of
48
Vdc
at
1.2
Amps.
The
converter
is
equipped
with
a
6-foot
(1.8
m)
DC
power
cable
which
is
terminated
with
an
RJ-45
male
connector.
The
converter
is
powered
by
120–240
Vac
(50–60
Hz)
power
which
is
supplied
though
a
standard
three-conductor
AC
power
cord.
The
120
Vac
power
cord
is
6
feet
(1.8
m)
long
and
is
provided
with
the
converter.
15988-A
Figure 10. AC/DC Power Converter
3.4 Optical Options and Requirements
Each
DHU
and
its
associated
DEU’s
and
DRU’s
are
connected
over
a
pair
of
optical
fibers.
One
fiber
transports
the
forward
path
optical
signal
and
the
other
fiber
transports
the
reverse
path
optical
signal.
Either
62.5
or
50
micron
core
multi-mode
optical
fiber;
or
9
micron
core
single-mode
optical
fiber
may
be
used
for
the
optical
transport
connection.
With
62.5
micron
core
fiber,
the
optical
path
may
be
up
to
500
meters
in
length.
With
50
micron
core
fiber,
the
optical
path
may
be
up
to
750
meters
in
length.
With
9
micron
core
cable,
the
optical
path
may
be
up
to
10
kilometers
in
length.
Single-
and
multi-mode
fibers
may
be
used
in
the
same
system.
A
diagram
of
the
optical
connections
is
shown
in
Figure
11.