Operating instructions
AC-10
ADAPT-A-COM
INSTRUCTION
SHEET
2-WIRE
MODE
BALANCING:
If
your
Clear-Com
system
is
supported
by
an
older
PS-3000
Power
Supply
or
a
CS-200
Main
Station,
turn
the
master
gain
control
on
he
rear
panel
of
the
Main
Station
fully
counter-clockwise.
Newer
Main
Stations
and
Power
Supplies
do
not
have
a
master
gain.
1)
Turn
both
gain
controls
on
the
AC-10
to
the
10
o'clock
position.
2)
Plug
a
standard
Clear-Com
headset
into
the
4-pin
XLR-Iype
connector
marked
"Test
Headset'
on
the
AC-10
front
panel.
3)
While
listening
on
the
headset,
push
the
A
balance
momentary
switch
and
adjust
the
A
balance
trimpol
for
minimum
tone
in
the
headset.
Repeat
this
procedure
with
the
B
balance
switch
and
trimpot.
If
the
unit
starts
to
oscillate
or
motor-boat,
back
off
both
gain
controls
slightly
and
re-balance.
4)
Disconnect
the
test
headset.
3-/4-WIRE
MODE
BALANCING:
The
procedure
is
the
same
as
for
the
2-wire
mode,
except
the
B
balance
is
inoperative.
ADDITIONAL
NOTES:
1)
The
test
tone
levels
heard
in
the
system
are
affected
by
the
Transmit
and
Receive
gain
control
settings.
2)
Attempting
to
get
too
much
gain
from
either
system
can
cause
instability
and
oscillation.
3)
If
you're
interfacing
to
a
TELCO
line
and
cannot
obtain
a
satisfactory
null
on
the
B
balance,
the
value
of
capacitor
C-39
should
be
increased
(see
schematic).
Try
adding
from
.05
uF
to
.1
uF
across
the
existing
cap.
AC-10K
ADAPT-A-COM
WITH
HOLDING
COIL
OPTION
The
AC-1
OK
Adapt-A-Com
can
interface
Clear-Com
with
standard
telephone
systems.
When
your
AC-1
OK
has
the
holding
coil
option
and
is
connected
to
a
"TELCO"
line,
the
user
may
dial
an
outgoing
call
from
a
telephone
extension,
switch
the
AC-10K
to
"Phone
Hold",
and
then
hang
up
the
receiver
to
keep
the
party
on-line
for
intercom
purposes.
Likewise,
an
incoming
call
may
be
answered
by
the
AC-1
OK
that's
in
the
"Hold"
condition
(instead
of
lifting
the
telephone
receiver
off
the
hook).
When
the
phone
rings,
set
the
Holding
Coil
switch
(on
AC-1OK
front
panel)
to
the
"Phone
Hold"
position.
The
AC-1OK
effectively
answers
the
phone,
connecting
the
caller
to
the
intercom
system.
The
red
LED
adjacent
to
the
switch
glows
to
indicate
that
the
telephone
line
is
seized.
The
Clear-Com
holding
coil
circuit
provides
a
simulated
termination
across
the
AC-10K
to
maintain
its
stability.
This
termination
is
automatically
applied
when
the
DC
voltage
on
the
TELCO
line
input
is
removed.
For
proper
operation,
the
holding
coil
circuit
should
be
used
only
on
a
standard
TELCO
line
"wet"
pair,
i.e.,
a
telephone
line
with
a
DC
voltage
across
it.
For
interfaces
with
non-TELCO
"dry"
two-
wire
lines,
the
holding
coil
is
not
needed
and
the
internal
switch
on
the
holding
coil
module
shold
be
set
to
bypass".
WARNING:
To
prevent
damage
to
the
Holding
Coil
circuitry;
when
the
AC-10H
is
used
as
an
interface
to
TW
(RTS
type)
systems,
the
intenal
slide
switch
(S1,
on
the
PCB)
MUST
be
set
to
"BYPASS-.
810060Rev.C
10/90
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