Service manual

Signalling
Configurations
in
Multi-Channel
Systems
In
normal
circumstances,
the
CALL
light
on
a
two-channel
remote
station
lights
only
when
someone
signals
on
the
channel
that
station
has
selec-
ted
for
communication.
This
is
because
the
Visual
Signal
travels
on
the
audio
line
in
the
form
of
DC
voltage.
A
simple
modification
may
be
made
to
the
the
system
wiring
so
that
stations
which
are
switched
to
one
channel
will
respond
to
a
call
signal
on
the
other
channel.
This
modification
may
be
applied
in
both
directions,
so
that
all
stations
will
indicate
a
call
signal
from
either
channel,
white
still
maintaining
two
completely
separate
inter-
com
channels
(diagram
shows
how
Channel
A
can
send
signals
to
Channel
B):
~~~~~~~~~~~A
a
DIODES
(4)
acng
0
|
n
In-Line
Isolation
h14TYP
In
certain
applications
you
may
want
to
isolate
conversations
in
one
section
of
the
system.
Clear-Com
offers
Model
BA-1
In-Line
Isolator,
which
blocks
intercom
audio
while
allowing
DC
voltage
to
flow
to
an
isolated
"leg"
of
the
system.
The
BA-i
allows
one
channel
to
support
several
simultaneous
and
inde-
pendent
conversations.
The
main
station
cannot
communicate
with
the
isolated
legs
of
the
system.
Private
local
conversations
can
go
on
along
a
common
interconnect
line
without
adding
great
lengths
of
cable
or
additional
main
stations.
You
may
incorporate
any
number
of
BA-I
Isolator's,
as
long
as
the
capacity
of
the
main
station
is
not
exceeded
by
added
remote
stations.
There
are
a
variety
of
ways
to
incorporate
the
BA-i
into
a
system.
For
instance,
you
can
plug
the
BA-1
directly
into
a
remote
station's
exten-
sion
(output)
connector,
a
main
station's
channel
output
connector,
or
between
two
runs
of
cable
on
any
channel.
This
diagram
illustrates
two
ways
of
isolating
any
section
of
your
system:
;a~~~~~
MTATIN
BA-11
STATION
||----I-S-LATOR
BA-1
_l
ISCILAT
S
10
EL;S
v
~~~~~~~~~~