Service manual
Il-B.
Cable
Considerations
The
MS-400A
contains
12
XLR-type,
3-pin
Portable
remote
stations
such
as
belt-
connectors:
two
male
and
one
female
per
packs
each
have
a
pair
of
input
and
out-
channel.
Female
connectors
facilitate
put
connectors;
when
Installing
a
system
system
wiring
when
more
than
one
power
that
includes
these,
you
can
daisy-chain
supply,
or
main
station,
is
connected
to
many
stations
along
one
interconnect
any
of
the
channels.
Cable
runs
from
the
path.
Or,
you
can
use
Clear-Com's
line
rear
panel
to
connect
with
all
remote
splitter
(one
input,
three
outputs)
to
stations.
Allow
three
inches
behind
the
feed
individual
lines
to
station
inputs
unit
for
cables
to
extend
from
the
rear
(see
diagrams
on
the
following
pages
for
panel;
avoid
sharp
bends
in
cabling.
various
configurations).
Daisy-chaining
and
line
splitting
decrease
the
amount
Depending
upon
your
application,
you
of
cable
required
and
simplify
installa-
will
run
separate
cables
for
each
chan-
tion.
nel
going
to
the
single-channel
remote
stations,
or
two
channels
(any
combina-
PERMANENT
INSTALLATION
CABLE
tion)
together
to
two-channel
remote
We
recommend
you
use
vinyl-insulated
and
stations
(crosstalk
considerations
dis-
jacketed
cable
for
connections
to
perma-
cussed
later
in
this
section).
nently-installed
stations;
it
costs
less
and
is
easier
to
pull
through
conduit
When
choosing
interconnect
cable,
keep
than
the
rubber-insulated
cable.
the
following
considerations
in
mind:
You
must
use
low
capacitance
cable.
We
I)
DC
resistance
of
the
ground
or
common
suggest
you
try
BELDEN
8762
(20
gauge,
conductor
affects
crosstalk.
In
per-
stranded)
for
applications
up
to
500
manent
installations,
do
not
use
wire
feet,
and
BELDEN
8760
(18
gauge,
stran-
smaller
than
20
gauge,
stranded
(ex-
ded)
for
up
to
5000
feet.
W
cept
runs
shorter
than
100
feet).
Keep
the
total
resistance
of
the
if
conduit
is
available
when
installing
ground
under
2
ohms.
permanent
remote
stations,
run
intercon-
nect
cables
through
the
conduit
to
each
2)
The
capacitance
of
the
interconnect
wall-
or
console-mounted
unit.
NOTE:
cable
affects
the
frequency
response
chassis
ground
and
signal
ground
(XLR
and
sidetone
stabilty.
Total
capaci-
connector
Pin
1)
are
NOT
the
same
point.
tance
should
not
be
greater
than
.25
DO
NOT
connect
the
chassis
to
Pin
1.
microfarads
(capacitance
between
con-
The
chassis
is
insulated
from
the
signal
ductor
and
shield;
equivalent
to
an
ground
with
a
capacitor
(.01
microfarad,
intercom
system
containing
5000
feet
1.4
kv).
This
eliminates
the
hum
and
of
cable
at
50
pF
per
foot).
potential
shock
hazard
that
can
arise
if
stations
are
at
a
different
ground
3)
Clear-Com
Systems
operate
best
with
potential.
cable
that
has
no
more
than
35
pF
from
conductor
to
conductor,
and
no
In
some
situations,
existing
wire
in
a
more
than
70
pF
from
conductor
to
conduit
may
be
used;
consult
the
factory
shield.
for
guidelines.
PORTABLE
INSTALLATION
CABLE
In
installations
where
conduit
is
NOT
Typical
cable
for
portable
system
inter-
used,
and
equipment
doesn't
share
a
connection
is
rubber-jacketed,
two-con-
common
ground,
it
is
good
engineering
ductor,
shielded
microphone
cable.
We
practice
to
run
an
additional
ground
suggest
you
try
BELDEN
8413
(24
gauge,
wire
to
tie
all
chassis
together
(this
stranded)
for
connections
totalling
500
decreases
susceptibility
to
electrical
feet
or
less,
and
BELDEN
8412
(20
gauge,
noise
fields).
S
stranded)
for
connections
running
from
500
to
5000
feet.
--
continued--
4