User Manual
ADCP-75-136 • Issue 1 • November 2002
Page 6
©
2002,
ADC
Telecommunications,
Inc.
2.1.7 Cooling
Continuous
air
flow
for
cooling
is
provided
by
dual
fans
mounted
on
the
right
side
of
the
housing.
A
minimum
of
3
inches
(76
mm)
of
clearance
space
must
be
provided
on
both
the
left
and
right
sides
of
the
DHU
for
air
intake
and
exhaust.
An
alarm
is
provided
that
indicates
if
a
high
temperature
condition
(>50º
C/122º
F)
occurs.
The
fans
may
be
field-replaced
if
either
fan
fails.
2.1.8 User Interface
The
DHU
user
interface
consists
of
the
various
connectors,
switches,
terminals,
and
LEDs
that
are
provided
on
the
DHU
front
panel.
The
DHU
user
interface
points
are
described
in
Table
1
and
indicated
in
Figure
3.
Table 1. Digital Host Unit User Interface
REF
No.
USER INTERFACE
DESIGNATION
DEVICE
FUNCTIONAL
DESCRIPTION
1
Ground
stud
Used
for
connecting
a
grounding
cable
to
the
DHU
chassis.
2
POWER
3-wire
AC
power
cord
connector
Used
for
connecting
the
AC
power
cord.
3
I/O
I/O
rocker
switch/
circuit
breaker
Provides
AC
power
On/Off
control
and
AC
power
over
current
protection.
4
OK/NOK
(Ports
1–6)
Multi-colored
LED
(Red/Green/Yellow)
Indicates
if
the
DRU
or
remote
DEU
connected
to
the
optical
port
is
normal
or
faulty
or
if
the
reverse
path
optical
input
from
the
DRU
or
remote
DEU
is
normal
or
lost.
(see
Note)
5
ON/OFF
(Ports
1–6)
I/O
rocker
switch
Enables
or
disables
corresponding
electrical
and
optical
ports.
6
DC
PWR
(Ports
1–6)
RJ-45
jack
(female)
Used
for
connecting
a
DRU
cat
3
or
5
power
cable
to
the
designated
DC
power
jack.
7
FIBER
(Ports
1–6)
LC-type
optical
transceiver
Used
for
connecting
each
DEU
or
DRU
forward
path
and
reverse
path
optical
fibers
to
the
designated
optical
port.
8
UNIT
Multi-colored
LED
(Red/Green/Yellow)
Indicates
if
the
DHU
is
normal
or
faulty.
(see
Note)
9
OVERDRIVE
Multi-colored
LED
(Red/Green/Yellow)
Indicates
when
the
forward
path
RF
input
power
is
overdriving
the
DHU
digitizing
circuitry.
(see
Note)
10
MAJOR
MINOR
Screw-type
terminal
connector
(14–26
AWG)
Used
for
connecting
an
external
alarm
system
to
the
DHU.
Includes
normally
open
(NO),
normally
closed
(NC),
and
common
(COM)
wiring
connections.
11
RF
IN
N-type
female
RF
coaxial
connector
Used
for
connecting
the
forward
path
RF
coaxial
cable
to
the
DHU.
12
RF
OUT
N-type
female
RF
coaxial
connector
Used
for
connecting
the
reverse
path
RF
coaxial
cable
to
the
DHU.
Note:
A
more
detailed
description
of
LED
operation
is
provided
in
Section
5.