User Manual
ADCP-75-136 • Issue 1 • November 2002
Page 21
©
2002,
ADC
Telecommunications,
Inc.
required
to
link
the
DHU
with
the
interface
device
and
the
interface
device
with
the
BTS.
In
a
remote
interface,
coaxial
cables
are
required
to
link
the
DHU
with
the
interface
device
and
the
interface
device
with
the
donor
antenna.
The
DHU
is
equipped
with
N-type
female
connectors
for
connecting
the
forward
and
reverse
path
coaxial
cables.
High
performance,
flexible,
low
loss
50-ohm
coaxial
communications
cable
(RG
400
or
equivalent)
should
be
used
for
all
coaxial
connections.
3.6 System Expansion Planning
The
DEU
enables
6-way
expansion
of
any
optical
port.
This
makes
it
possible
to
add
more
DRU’s
without
having
to
install
additional
DHU’s.
Each
DHU
is
equipped
with
six
optical
ports.
If
more
than
six
DRU’s
are
required
by
the
application,
a
DEU
may
be
connected
to
one
of
the
optical
ports
at
the
DHU
which
expands
that
port
to
six
ports.
If
still
more
optical
ports
are
required,
then
a
second
DEU
may
be
connected
to
the
DHU
or
a
second
DEU
may
be
connected
to
the
first
DEU.
The
ability
to
cascade
DEU’s
in
parallel
or
in
series
provides
unlimited
flexibility.
It
is
physically
possible
to
connect
an
unlimited
number
DRU’s
to
the
DHU
through
the
installation
of
DEU’s.
The
total
number
of
DRU’s
that
can
be
served
is
limited
by
the
cumulative
noise
effect
caused
by
antenna
combining.
This
number
cannot
be
determined
until
the
radius
distance
of
coverage
required
at
the
DRU
antenna
is
determined
and
the
path
loss
attributed
to
the
structure
are
known.
The
system
design
requires
that
the
carrier
to
noise
differential
be
greater
than
the
customer’s
desired
signal
to
noise
ratio.
If
it
is
likely
that
the
system
will
be
expanded
in
the
future,
locate
the
DHU
in
such
a
way
that
it
can
be
used
as
a
hub
for
an
expanded
system.
It
should
be
noted
that
a
DEU
can
be
used
as
an
optical
regenerator.
A
DRU
may
sometimes
need
to
be
located
at
a
point
that
is
beyond
the
distance
limitation
imposed
by
the
optical
fiber.
The
solution
is
to
install
a
DEU
at
the
maximum
optical
fiber
length
from
the
DHU.
This
provides
an
additional
500
m,
750
m,
or
10
km
(depending
on
the
fiber
type)
of
optical
fiber
length
beyond
the
DEU
for
connecting
the
DRU.
3.7 DRU Antenna Options
Various
antennas,
shown
in
Figure
12,
are
available
from
ADC
for
use
with
the
DRU.
All
antennas
include
a
6-foot
(1.8
m)
long
50-ohm
coaxial
cable
(equipped
with
SMA
male
connector)
for
connection
to
the
DRU.
The
DRU
is
equipped
with
an
SMA
female
connector
for
connecting
the
antenna
cable.
The
DRU
antennas
are
designed
for
unobtrusive
mounting
within
an
office
environment.
Each
type
of
antenna
provides
a
specific
coverage
pattern
in
order
to
accommodate
the
shape
of
the
area
where
coverage
is
required.
The
ceiling-mount
omni
directional
antenna
is
designed
to
mount
in
the
center
of
the
coverage
area.
The
directional
panel
antennas
are
designed
to
mount
vertically
on
one
side
of
the
coverage
area
or
in
the
corner
of
the
coverage
area.
The
ceiling
mount
hallway
antenna
is
designed
to
mount
in
the
center
of
long
corridors.
Antennas
other
than
those
offered
by
ADC
may
also
be
used
if
required.