User Manual
ADCP-75-136 • Issue 1 • November 2002
Page 10
©
2002,
ADC
Telecommunications,
Inc.
2.3 Digital Expansion Unit Description
The
DEU,
shown
in
Figure
6,
serves
as
a
service
expansion
unit
and
line
extender
for
the
Digivance
ICS.
The
DEU
provides
the
following
basic
functions:
• Optical
interface
to
the
DHU
and
up
to
six
DRU’s
or
DEU’s
• Conversion
of
the
forward
path
digitized
optical
signal
to
an
electrical
bit
stream
• Splitting
of
the
electrical
bit
stream
into
six
separate
bit
streams
• Conversion
of
the
six
forward
path
electrical
bit
streams
into
six
digital
optical
signals
• Conversion
of
up
to
six
reverse
path
digital
optical
signals
into
six
serial
bit
streams
• Combining
of
the
six
reverse
path
serial
bit
streams
into
a
single
digital
composite
signal
• Conversion
of
the
single
digital
composite
signal
to
a
digital
optical
signal
• DC
power
for
powering
the
DRU’s
• Alarm
transport
via
the
optical
fibers
FRONT PANEL
CABLE MANAGEMENT
TRAY
MOUNTING
BRACKET
(BOTH SIDES)
17270-A
3.5 INCHES
(89 mm)
11.4 INCHES
(290 mm)
15.3 INCHES
(389 mm)
17.2 INCHES
(437 mm)
Figure 6. Digital Expansion Unit
2.3.1 Primary Components
The
DEU
consists
of
two
electronic
circuit
board
assemblies
and
a
power
supply
that
are
mounted
within
a
powder-coated
sheet
metal
enclosure.
The
metal
enclosure
provides
a
mounting
point
for
the
electronic
assemblies
and
serves
as
a
heat
sink.
Except
for
the
fan
units
and
optical
transceivers,
the
DEU
components
are
not
field
replaceable.
The
DEU
is
designed
for
use
within
a
non-condensing
indoor
environment
such
as
inside
a
wiring
closet
or
cabinet.
All
controls,
connectors,
and
indicators
are
mounted
on
the
DEU
front
panel
for
convenient
access.
Cable
management
functions
for
the
power
and
fiber
optic
cables
are
provided
by
a
cable
management
tray
that
extends
outward
from
the
DEU
front
panel.
2.3.2 Mounting
The
DEU
may
be
used
in
both
rack-mount
and
wall-mount
applications.
For
rack
mount
applications,
a
pair
of
reversible
mounting
brackets
is
provided
that
allow
the
DEU
to
be