Instruction manual

DESCRIPTION
/ Clear-Corn
CS-222
2-Channel
Main Station
O
SECTION
1
DESCRIPTION
OF THE
CS-222
2-CHANNEL
INTERCOM
STATION
CLEAR-COM
CONCEPT
Clear-Com
is
a closed-circuit
intercom
system
that consistently
provides
high-clarity
communication
in high-noise
and
low-noise
environments.
A basic
system
consists
of a
single-
or multi-channel
power
supply or
main
station connected
to various
single-
or
multi-channel
remote
stations,
such as
beltpacks
and
loudspeaker
stations.
Clear-Com
manufactures
a
wide variety
of
both portable
and
fixed-installation
units.
All
are
compatible
with
each
other.
Clear-Com
intercom
systems
can
also
interface
with
other communication
systems
and
devices.
Clear-Com
stations
are interconnected
with two-conductor,
shielded
microphone
cable,
using
3-pin
XLR
connectors.
One
wire
carries
the
DC
power
(28-30
volts)
from
a
main
station
or
power
supply
to
all remote
stations,
and
the
other
wire carries
2-way
(duplex)
audio
information.
The shield
acts
as a common
ground.
One
termination
(per
channel)
Is
needed
throughout
the
intercom
network,
and is
usually
located
in the main
station
or
power
supply.
Clear-Com
is a
distributed
amplifier
system;
each
main
and remote
station
houses
its
own mic
preamplifier,
headset
or
speaker
power
amplifier,
and
signaling
circuitry.
The
Automatic
Headset
Detection
circuit
shuts
off a station's
mic
pre-amp
when
the headset
is disconnected,
so
background
noise
on the
line
is not
increased
by an
unused
yet on-
line station.
Low-impedance
mic
input
lines
(200
Ohms)
and
specially
designed
circuitry
make
Clear-Com
channels
virtually
immune
to RFI and
dimmer
noise.
Clear-Com
main stations,
power
supplies
and certain
remote
stations
each
have
an
auxiliary
program
input
with its
own volume
control,
which
allows
an
external
audio
source
to be
fed to the
intercom
system.
Visual
Signal
Circuitry
(CALL
Lights),
a standard
feature
on
most main
and
remote
stations,
allows
the
user to
attract
the attention
of
operators
who
have removed
their
headsets.
Depending
upon
the type
of main
and remote
stations
selected
and assuming
that
enough
DC
power
is available,
a
maximum
number
of remote
stations
from 10
(all
speaker
stations)
to 30
(all headset
stations)
can
be distributed
along
a mile of
wire.
Remote
stations
bridge
the
intercom
line at
a very high
impedance
(>10
KOhms),
and
place
a minimum
load on
the line.
The audio
level
always
remains
constant,
and
does
not fluctuate
as stations
leave
and
join the
network.
The
28-30
volts DC
provided
by main
stations
and
power
supply units
enable
remote
stations
to operate
with
minimal
current
(25 mA.
quiescent
for
headset
stations,
50 mA.
quiescent
for speaker
stations)
while
generating
extremely
loud listen
volumes
(greater
than 110dB
SPL
using
Clear-Com
Headsets).
The highervoltageand
lowcurrent
keep
voltage
losses
to an
absolute
minimum
in long
lines.
If the supply
voltage
drops
due
to
the
addition
of great
length
of cable
or many
more
stations,
Clear-Com
equipment
will
continue
operating
with less
than
12 volts
available.
0
2/92 Rev.
1.1
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